to be 100% honest, staff is pretty much just one dice away from the best martial versatile weapons.
d6-d8 vs d8-d10.
which is essentially +1 damage on average. So if you find a good staff, with bonuses, or special traits. it wouldn't really be crazy to use it.
a +1 staff does more consistent damage than a naked longsword.
as to losing bless, not really, front liners usually have high constitution, and high AC. attacks often miss, and they beat the con save often. Bless is given to clerics and paladins who are generally front liners. Also since concentration is one per player, you lose little by having some one else do it, if they can.
that all said, it doesn't really matter that much, the game isn't really balanced on max efficiency play/builds very often
