Well it stops your ISP/your employer/somebody on your local network from snooping through your traffic, but you're just moving the problem somewhere else.
Instead of your ISP or whoever looking at your traffic, you have to worry about the VPN provider or the VPN provider's ISP looking at the traffic instead.
Additionally I don't see what gambling has to do with anything
(Red highlighting mine)
One of the reasons to use a VPN is to disguise your location. Since the gambling sites are apparently illegal in the USA, I am guessing that with a good VPN that has service (servers) outside the USA that gambling might now be accessible to Americans. I have not tried this possibility out, however. If anyone (American or whoever) HAS tried this out, well tell us!