what about devs too scared to put their CC no in the till coz they've heard horror stories about being overcharged for mistakes? Just recently had to sort out a feature that a junior dev created using openstreetmaps coz they didn't want to be on the hook by putting their card into google maps... It was for an internal portal, usage wasn't even high enough to hit the monthly free tier!
Hour 1 experience also matters.
Perhaps I've misunderstood the situation, but if I were working as a dev at a company and was expected to provide my own card details to pay for APIs, I would walk out the door.
The dude bounced off google maps as soon as he saw the form to enter payment info and went straight to open street maps.
As he should. Unless you have in written form that the company will cover the exact expense, then no one should use a personal CC for work use.
from your comment history i see you're european.Europeans have way more protections and assurances in cases like this, india is a very different business environment...
Sounds like a happy ending.
On (1), if you get to say the 14th of the month and run out of budget, what would be the expected behaviour? - shut down all your services? delete all your data so that's not incurring a charge too? It'd probably have to be configurable on a service by service basis, and that's an awful lot of complexity to introduce for a tiny minority of their revenue base.
On (2), their billing systems are almost certainly eventually consistent in logging and charging usage, so they'd either have to shut you down early in anticipation of delayed charges, or let any delayed charges bring you over budget. Either is liable to make customers fairly unhappy one way or the other.
The TL;DR version - it'd be nigh on impossible to have good UX with such a feature, would be complicated to implement, and it's not likely to move the needle on any metric they really care about considerably.