Back when I experimented with getting ChatGPT by paying for API access rather than the official subscription, the credit was denominated in money, not in tokens.
Compute does whatever it does, but $5 sitting in an account to be spent on tokens at some arbitrary time in the future, earns money for OpenAI etc. even when they didn't make it expire.
Gift cards do not expire because laws were passed to prevent it. No such laws exist for AI credits, so companies will do what is most profitable.
The gift card analogy breaks down a bit: a gift card doesn’t get more expensive for the store to redeem later. Compute can.
Back when I experimented with getting ChatGPT by paying for API access rather than the official subscription, the credit was denominated in money, not in tokens.
Compute does whatever it does, but $5 sitting in an account to be spent on tokens at some arbitrary time in the future, earns money for OpenAI etc. even when they didn't make it expire.
AI credits expire because they make the least money off you if you actually use your full quota, now or later.
Accounting purposes, I guess.