Is it really that unusual? When you attach an image or a video, it gets converted to tokens you don’t see, at a rate that is proprietary to the model. You pay for those tokens, but don’t see them. Even how text is converted to tokens is a property of the dictionary, which is opaque for proprietary models.

There are features of input and output that are opaque to you, but that you pay for. Part of how model providers chose to run their service.