The issue is whether you want to cater to established conventions (both in mathematics where 1-based indexing is typical, but non-mathematicians will also simil

The issue is whether you want to cater to established conventions (both in mathematics where 1-based indexing is typical, but non-mathematicians will also similarly use 1-based counting), or you want to cater to what is most logical. I suspect the main reason 1-based seems convenient for some things is because of convention. Note that 0 wasn't even really used in mathematics until hundreds of years after our system of counting years was created. Since our year counting is 1-based, we end up with odd things like "2019" being the "19th year" of the "21st century" as opposed to "2018" being "year 18" of "century 20". I suspect it's also fairly unintuitive that the current century began in the year "2001" rather than "2000".