Blockchain will be used not only in gambling and a payment gateway, but also it will be used on every branch of life. We have to wait to see what happen finally.
Well, the OP was not asking about blockchain uses but he was asking if blockchain could the only best option gambling gaming industries which I will say yes because in the situation where trust is needed while cheat is totally not acceptable it will get if blockchain was used.
It's already applied to some online crypto casino's and if you will hear out 'crypto casino' there will be a thinking that it's built through blockchain. I'm not against that blockchain will be used in every aspect of our lives.
But yeah, it's different and data inside the blockchain network can't be changed so it's really going to help who will adopt it. Abusers can easily caught out if the technology they run is blockchain. More improvements will be done and it's just getting better.
Integration of blockchain technology in the gambling industry might really help in fighting the rigged systems that are common in casinos. This will ensure higher chances of winning from the gamers' side. And with this enhancement of the gambling system, non gamblers might be attracted to try this industry. Thus, increasing the number of users and so the gambling industry will be a hit. Time will tell how far we are now in achieving this kind of environment in the gambling world. There are already few projects offering the utilization of blockchain technology in their betting platforms. We will know how efficient this system would be.