Originally Posted by ShelledPants
Neg, it's so your team mates don't go rushing in after what might have been a DD.
And it makes the enemy react.
Originally Posted by FirestormX
My understanding is that it's mostly for safety. You could say "heads up, there's a heavy projectile being lobbed in your direction", but specifying that it's a grenade has the added effect of letting newbies know what's going on.
The way it seems to be being taught and the way I and most people I know were taught is as follows
Grenade = incoming
Frag out = outgoing
Regardless, Shelled is on the ball, it's communication, so that your guys know what you're doing and you know what they're doing.