When I need flash (rarely), I upload. Then uninstall again. It’s that simple.
The typical computer user would find it annoying if they had to re-install Flash Player every time they wanted to watch a YouTube video.
I haven’t noticed any problems with Flash on Mac OS X. Steve Jobs recently voiced some complaints about Flash being too inefficient for iPhone usage, but that issue may be resolved in about two weeks when the 3G iPhone is expected to be announced.