As i see the most casinos don`t have "gambling" in their names but have smth about gambling. For example - Stake. Very short and memorial brand name. I think "stake.com" gamblers will remember but not "gamblingwiththebestodds.com " Possible that it will be harder for promotion but i think that you can`t get easy and short "gambling" domain names nowadays, only smth near gambling. Like as Stake.
The point is, it's much better if you have a gambling site then it is much better if it has a good name where it is easy to remember which belong to having a good brand name and then the functionality which you already know it. Having gambling on the brand name does it's job where it could be found faster using search engine but I don't think many people will think that I can't trust this site as it could be a scam site. As you have said, most reputable gambling sites in this forum does not have gambling in their names.