Since you call this a PR promotion, someone who's into it, can do anything for people to buy the idea they share for the project they are marketing its project.

However, I have known Drake to be an ambassador to Stake. He can't be spending millions of dollars every month on gambling without the Stake board working in hand with him on promoting them. This may be what we don't know about, the terms involve in this form of marketing  between Drake and Stake. What we will get to know about is the amount Drake posted of his gambling bets on Stake. What plays out after, is what we don't know. Drake won't reveal it to us