Well Caesars just mandated mask wearing in all its properties, and NV rules may soon change to mandatory mask wearing in all casinos (my guess). Exceptions are when eating and drinking (obviously).
I advise players to also look for more isolated areas of casinos where they can make sure not to sit too close to others. I did not find this a problem on my one excursion so far to the Gold Coast for about 2 hours of play. I think you can be safe gambling if you take your own precautions. To make sure no one sits next to you at slot machines, remove chairs if necessary and so on. Table play is a bit dicier because you can't as easily wipe down felt or dice or prevent people from coming to stand behind you suddenly and so on.
As for mask wearing, it really isn't all that annoying for a few hours. If you find it so, try getting several different kinds of masks. I recommend taking several different masks with you so that you can switch off if necessary. The medical style disposable masks are now finally in good supply at places like amazon.com and frys.com if you cannot find them in your local store or pharmacy, and they cover quite well and work well. Cloth masks are trickier — I ordered two nice ones from Grace and Lace only to have them SHRINK when I machine washed and dried (I will hand wash any reusable masks from now on). You can also try a personal fan or removing the mask for a moment if it gets uncomfortable and then pulling it back in place. It just takes a little patience and getting used to..
I believe masks will prevent a certain amount of particles from getting in (it may be small but anything is helpful) as well as keeping others safe if you unknowingly have the virus and talk, sneeze, or cough. Countries where mask wearing is common have done a lot better in slowing the virus than those where people do not wear masks. So be kind to yourself and your fellow men and women. The virus can not only be deadly to some but also cause long-lasting effects and bad illnesses to other people. All age groups can be affected. So be nice to everyone including yourself by undergoing the slight inconvenience of mask wearing.