The admin should strive or work to get both a brand name that has a recall or is very much familiar with gambling, everything starts with a name and they will build their trust rating around that domain name, if they got a good brand name then they are on a good start and they can work on building their functionalities, these two go together it's hard not to have one, but the casino can still build its reputation without a good brand name.
I don`t sure that the brand name must be much familiar with gambling. We see such sites every day and often they sounds the same. But you`re right that brand name can`t be just the common word. And it must be chosen before the start - it can be used in marketing campaigns. And the site functionality is the main thing what will help to attract new gamblers.