Then you can share apps...though I think there is a difference between iPhones and Android phones in that iTunes is independent of the iPhone's daily use. In other words you can use the iPhone without ever using iTunes (I believe). This may make sharing apps on Android phones more difficult is you have to sign into that Gmail account to download the paid apps again to share. But by signing onto that Gmail account pretty much everything related to that Gmail account also gets shared as well (email, calendar, contacts) etc. I am sure you can choose to not sync anything, but then that does a lot to cripple many functions that Android good for.
In short, sharing apps might also just mean sharing everything else...and that is probably not a good thing.