Why Shirk?

[Alphras]

Shirk is not really about tank swaps (although it doesn't hurt), it is allowing the tanks to forgo the enmity combo and also Tank a lot of the time outside of tank stance without ever worrying about aggro.

If you provoke and instantly shirk it is basically an instant 25% enmity increase. Very strong in coordinated groups.

Also there is no real alternative if the fight doesn't need stun or silence.