Good guess. 😂

But the reason why I see it as a problem is that numbers imply order and these don't have any particular order, once you get past 00 and 01.

But the ordering of numbers allows a dev to just reserve 6000-10000, and come up with some harebrained scheme were he uses kind numbers as counters, or something.

And numbers are more limited because they're fewer characters to combine. You can get more combinations out of a short string than a long integer. That's why our keys contain letters.

So, no upside, but some downside.