Alibi.
Though I use it as a pve tank and I use it on bosses just to proc the minor prophecy for my DDs without rooting anything with it. So I guess I save a bit of magicka now. It certainly does not make it more attractive though. I would prefer any morph of talons every day if I could.
Auri-El is my lord,
Trinimac is my shield,
Magnus is my mind.
I think they should additionally split out 20% of the dmg made by the dmg morph, and put it on all morphs on targets hit, that way the small dmg (unattractive dmg) will proc the blood magic passive, healing you a small bit (10% of max hp) making it much more attractive for tanks in pve (especially the major vitality morph)
I would rather zos mess with the two morphs to make them different. Sorc has the issue where almost all of the morphs are just ever so slightly different....but one is pointless and never used.
For example with encase, one morph could be the root+vitality+damage. The other morph could be the opposite, snare/root immunity. Which opens the doors to group utility or counterplay options. If there was a 4-5k mag 8s snare immunity, I for sure would find a way to use it on my stamsorc, even though the steep cost.