Is "Warrior of Valkyrie" skill worth investing?

[Handel]

The skill which gives to a skald 90% rez of the losses from the random group? I presume it is rounded down so if you lose 1 black dragon you will not get it. I don't try to beat it on impossible with 0 losses but still it is easy to win most of the battles with no losses. Any *special* reason to take it?
Which reminds me - I play as Skald on impossible and am actually out of useful skald skills to take, providing I don't mix demons and humans etc.