Tesudo, SE inadvertently admitting the tank LB is worthless?

[Cabalabob]

So I was looking at the PvP action Testudo, and my immediate thought was "this is better than the tank level 1 and 2 LB..." It has a 180 second recast which can be reduced. It has a 15 second duration which is just as long as the tank LB and can be enhanced to 20 seconds. And the initial effect is 15% damage reduction for all party members, tank LB1 is 10% and can be enhanced to 25%, tank LB2 is 20%.

So in PvP PLDs have an ability that can be used regardless of party size, with a fairly short recast and is stronger than their limit break... Am I misunderstanding the concept of breaking limits here? Or does this not put into perspective how utterly bad the tank LB is that SE can make a PvP ability that is stronger than it...