This sounds like how you get (or at least used to get) free AWS and Azure credits in your first x years as a startup or until you met revenue thresholds. You wouldn't get as many, but, you didn't have to give up a share of your company, to my knowledge.
Were there actually larger credit grants that would've been in exchange for equity, or, is OpenAI doing something novel?
I have no idea, just a BigCo engineer! Like someone getting hooked... taxes are a Later Problem. Anyway, the deal sounds less like a 'mic drop' and more like something else hitting the table.
Say 'Whizbang Model 6.8' comes out and tokens burn ~5x faster; what to do? Agree to give up less of the business or hope for proportional growth? The two million that had been agreed is no longer truly available/applicable. How this and the equity 'shake out' are probably relevant.
At risk of upsetting people, token value is arbitrary. What model, what time of day? What transaction? All to say: I have no idea what the Tax Man or our fake business would want :) Above my pay grade, thankfully!
Reminder that "$2 million worth of OpenAI tokens" is meaningless and codes for "as much access to OpenAI infrastructure as Sam Altman feels like letting you have".