I feel like biggest advantages of using Bitcoin in online gambling platforms is to avoid some countries' regulations. It can be very hard to deposit local currency to bank account of gambling platforms. But its so much quicker and easier to do same with Bitcoin. Most countries don't follow Bitcoin transactions in such situations because its not exactly something illegal. Its legally grey area. It gives chance to many people around the world to gamble in 5 minutes.
It's not that easy since most casinos have to uphold the terms of their license and not allow people from countries where gambling is banned to play. If you use VPN to circumvent the restrictions, you can be banned from the casino and denied payment. I wouldn't call that the biggest advantage of bitcoin.
The real advantage of bitcoin casinos is anonymity of payments, where you don't have to use your bank account at all. All you do is transfer bitcoin and get it back, and then you can find a store or service that accepts direct, no KYC bitcoin payments and you're all set. You've gambled without anybody knowing, you've earned profit, and you've spent that profit, all anonymously.
Is it really necessary to spend the Bitcoins directly? You can simply just keep them and convert them to fiat later whenever you need cash, no one would know that you've got cash from withdrawing Bitcoins from a gambling platform, and you should be good that way too. Also, you will give yourself a hard time trying to find a store to spend your Bitcoins I'm sure.
Also, I think there are some casinos that allow their gamblers to use VPN without any issues, though I never tried it myself but I think Stake allows it, I never heard anyone saying that they've got banned from Stake for using a VPN.