Unless the cost of generating plummets - and I think we'll see a 10x decrease in that in the coming year or so - it'll probably be a credits system. I think this feature has the potential to quickly become Adobe's primary money maker. I think a lot of companies are suddenly finding themselves in a lot of money with the current hype, e.g. midjourney, openai, etc.
An Adobe employee wrote on Reddit that they plan to allow an unspecified limited number of generations per month, included in the current subscription (even if your subscription is annual). Beyond that there would be an extra fee for more credits, which might or might not roll over to the next month.
Unfortunately, the posts have now been deleted, but you can still see other people's reactions:
