I thought that casino/sportsbook was also accepting crypto payments. Or at least I've seen that in the past. Maybe they have now completely switched to Fiat payments, but then I think you still have the option to pay with bitcoin or other crypto.
I think they are fiat accepting casino before and the crypto gateway is just newly added to them because they see a potential market if they adopt bitcoin on their platform and guess they are successful with that since getting some good impressions will convert it to more costumers and also for sure their campaign will help them gain positive things especially they are here where the market is more bigger.
As a business whether you do start purely with crypto or fiat then you would be always minding about expanding the business not literally on adding more games or huge update but rather going with another payment gateway which would really expand the possible users that could play into their site.Basing on my observation and as part of their sigcamp then you could actually see it's relevance and probability on hooking players on this market.