You've called out two of the primary issues with addresses- first, assigning a designation to lots, and second, assisting someone in finding the place.

In the most GENERAL sense, addresses have historically been assigned by persons not familiar with an area to make recordkeeping easier. There are historical examples of conquerors attempting to codify traditional land names and designations when surveying newly subjugated territory to facilitate taxation; a famous example is the Domesday book.

Today's random entry on Domesday.org: Leckhampstead, in the hundred of Stotfold, in the county of Buckinghamshire, lord in 1086 was Gilbert Maminot. So today, that would be:

Gilbert Maminot, Leckhampstead, Stotfold, Bucks County

This is the way that addresses are done in many places still today, especially places with a strong rural heritage and relatively stable community populations. When I used to live in Ireland, I would get mail addressed like this: "The American at Tommy O'Riordan's, Templebeg, Kilnemanagh, Thurles, Tipperary". And the postman knew who it was.

Numbering became more fashionable in the early modern period (great scholarly article here: http://histoiremesure.revues.org/3942?lang=en) as cities expanded and "developments" became a real estate concept. A deed (without getting into the complicated history of deeds and real estate law, especially in the UK) might say something like, "the house and lands lying and being in the town of X, bounded by Y, Z, and R, known as Buckingham Palace", which would be an example of the old-style address. OR, it might say something like, "the house on Lot 8 of Mr. Stapleton's Development, bounded by the street where the Hay Market is, an alley, and Lots 6 and 7". This might be shortened for everyday purposes into "Number 8, Haymarket Street, Stapleton, London".

Once streets, buildings, and developments were planned- rather than "growing up" in the sense of use and tradition- it was easier to number buildings and lots. Grids were very fashionable in the late 17th and early 18th c (see early plans for cities like Savannah, GA), and rather than giving long directions of "bounded bys", it was easier to assign a number.

Which brings us to the other useful thing about addresses- finding the place in question. In the modern era of transportation, populations tend to be more transient- so the postman isn't likely to simply "know" your address. This was briefly solved in the US by addressing things "General Delivery, X Post Office", and people would come into the post office to check if they had mail. However, later in the 19th and 20th c, huge numbers of people moving constantly overwhelmed local post offices (in the US and elsewhere). So, numbered addresses became more common, along with numbered zones (US ZIP codes, UK post codes) rather than traditional townland or parish names, which made systematic tracking of mail easier. But where traditional names exist, people were loath to give them up in favor of numbers- so the numbers were simply appended. It's also a second layer of information, in case someone mistypes/misreads a numbered post code. More recently, places have resurveyed addresses for emergency purposes to make sure every address is unique and services won't be delayed simply because there are two "21 Birch Lane"s in Croydon.

TLDR: Addresses are 1) meant to identify a property, 2) get someone there. Traditionally, people either named a place by the informal means of "that's what everyone calls it", but in the modern era names are assigned in planning, along with numbers, to make record-keeping easier, especially because people are more transient.