Are barre chords REALLY nessacery?

Sometimes it requires more skill to not use a barre chord fingering, as string muting is often involved. For some musical genres, the more one plays (greater experience), the less one actually uses "full" barre chords -- especially when playing with others (very especially piano).

Pretty sure someone already pointed this out: barre chords are great for instant transposition. I see that as the major reason to know them.

-Greg