Main issue is that token are not equivalent across provider / models. With huge disparity inside provider beyond the tokenizer model:

- An image will take 10x token on gpt-4o-mini vs gpt-4.

- On gemini 2.5 pro output token are token except if you are using structure output, then all character are count as a token each for billing.

- ...

Having the price per token is nice, but what is really needed is to know how much a given query / answer will cost you, as not all token are equals.