Howcome would you figure it would be better not to reinstall upon launch, how big of a mod are you talking about here?
The launcher however can be set to operate as a normal installer/uninstaller too for the ones that prefer that. It's optional wether you'd like it to auto-uninstall after game-exit.
I found it handy with the auto-(un-)installer since you never really notice the extra loadingtime, it's just like a normal gamestart, but then again i didn't use mods of like 400Megs or so either ofcourse.
