Poker is more popular than casinos and the volumes are high, but the per player yield is low compared to casino players. It works both ways and I would suggest sticking to what you do best. But nothing stops you from a little diversification.
Most poker rooms added casino products to the product mix and have been successful in generating more revenues. Published figures are proof of this fact.
Most poker rooms don’t won the softwares and depend on the software providers for the additional casino games. Most of the times these extra plugins are not an ideal fit to the existing software and primarily wallet. Therefore some rooms may have taken off the casino products. Hope this helps.