The security risk is only there if the flash application is designed to attack you. The WGT flasch programs are not designed this way. Or if someone hacks the WGT servers and changes the programs to attack you while you are using them.
But Adobe will eventually abandon flash totally. And WGT will be screwed unless they rolled out a new non flash client before that happens. This will be a lot of "fun" for us when it happens.
But hopefully a lot of problems created by the programming mess the WGT developers made while maintaining the current source code will stop to plague us with the countless strange bugs introduced at every update.
A lot of them can only happen due to the developers having to work with the souce code of a poorly structured programming project.