The general reason is maths. Its a whole lot easier to do mathematics in the Hindu system of numbers than the Roman; as such many of the developments in rigorous maths were being done with this set of numbers.
The Hindu numbering system was progressively created between the 1st and 4th centuries (that is, it didnt spring up overnight). We know that by the 8th century it was in use in Persia by some of the greatest mathematical minds in history. Al-Khindi, one if the aforementioned minds, utilized the system to develop algebra, cryptography, harmonics, optics and others. These developments and those of other enlightened minds made their way into Europe by way of the Moors and interactions brought on by the crusades.
Hiya, you'll find a previous post, and links to several more here
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