Well there are several questions in here and as such several answers. Firstly, in regards to the wild and somewhat (in my opinion) drug induced theories as to Shakespeare NOT being the author of the works, I respectfully direct you to u/Taxpare answer to a similar type question here and u/Harmonia here.

But you crucially ask a question as to the worth of knowing it was the work of one man from Stratford. What do we gain?

Insurmountable treasures.

Allow me to elaborate: Shakespeare grants us a unique view not just into the Elizabethan mindset, but also the wider world of ideas, concerns and fixations.

For my own part I cannot even begin to measure the little insights and revelations he gives us of his world. What follows are just personal areas of interest in a many decade passion for the man all driven by his works.

I was drawn by the way he uses Greek myth to directly address Southwalks sex workers, which given The Globes proximity to the London Stews, no doubt made up a significant part of his regular audience. (Troilus and Cressida Act 5; Scene 10; Panderus speech).

It makes us ask- what was the relationship between the Winchester Geese and the Playhouses? And their players? It makes us wonder if the rumours of some kind of venereal disease afflicting him in later years was true?

(A more detailed link to prostitution in Shakespeare’s era is to be found here).

Is it the fact we know so many glove making terms because he mentioned it in almost every single one of his plays?

We ask- What can we infer from his final history play (Henry VIII) being not only written and performed after Elizabeth’s death, but staged in Blackfriars (the actual location of Henry VIII’s divorce depositions) and making Catherine of Aragon out to be such a sympathetic character? Why did he leave Fletcher to write the conclusion which hails Elizabeth as the saviour of the Tudors?

We have many questions about his religion (albeit ones which are hard to answer given his amazing studied ambivalence towards religion), but his purchase of the gatehouse at Blackfriars in March 10th 1613 (next door to the Blackfriars theatre), witnessed by the owner of The Mermaid (the Vinter John Jackson) and basically given to one John Robinson (who was a member of the recusant Fortescue household and possibly a young catholic priest); a house which two years after his death was given to John Greene and Matthew Morris ‘in accordance with the true intent of Mr Shakespeare’s will’- one wonders what said true intent was; (given that several years later this House, long identified as being a place where Catholics came together to celebrate mass, was infamous for its warren of tunnels and secret places for priests to hide in and above all some years later when a floor collapsed some years later in the adjacent building, killing 90 Catholics secretly gathered in mass (including some folks from Warwickshire) we begin to wonder about his religion, and the way Catholics hid their faith).

I must point out that the idea he harboured Catholic sympathies and it remained Catholic is the source of an absolute barnstormer of historical debate; I for one do subscribe to it BUT must concede the case is far from conclusive.

And these are only a handful of elements that I personally find fascinating.

There are literally hundreds more. And hundreds of thousands of scholars more learned and expert on these than I will ever hope to be.

By knowing those mighty works were the product of one man; by tracing his life, what deeds we see, what traces he left behind, we begin to gain a unique insight into his world.

We appreciate the vigour of his education at his local grammar school (then known as Kings New School); we begin to value how he impacted upon the world and it impacted upon him.

More importantly (and I say this as someone who moved to Stratford upon Avon once so I could utilise the resources of the Shakespeare Birthplace Trust) we can study his indelible impact upon the town; can trace him from childhood (son of a glove maker and former mayor) through success (the purchase of the largest house in the town, the mighty New Place in 1597), to death.

The fact that in records of Chapel Ward (where New Place was located) shows how his success in London related to his expenditure in Stratford. We know he had the wealth to buy land in Shottery and Old Stratford (including spending the not inconsiderable sum of £320 to purchase 107 aches of open fields outside of the town). We can match his success in London to his purchases in Stratford and this interest between his home (in Warwickshire) and his workplace (the capital) is an endless source of insight for exploring the relationship between he expanding city and the regions.

His is a fascinating, intriguing life; filled with many questions (as he was by nature it appears or perhaps for other more pertinent reasons, a private man) but his authorship of his works is not in doubt, nor the importance of the man himself.

Online resources (beyond the ones liked to in the above): A brief guide to the resources available from the Shakespeare Birthplace Trust- a phenomenal bunch of people, whose passion for the Bard is equalled only by (in my experience) their expertise. http://collections.shakespeare.org.uk/search/archive/page

References: *Donnelly, Ann & Woledge, Elizabeth; Shakespeare Work, Life and Times; 2012; Shakespeare Birthplace Trust

*Wood, Micheal; In search of Shakespeare; 2004; BBC Books.

*Duncan-Jones, K; Ungentle Shakespeare; 2001; Bloomsbury.