Not bleeding out. They're still Servants.

Normally, though, just waiting overnight is sufficient to deal with any injuries they have and even nearly cutting cut in half by Saber is something even EMIYA can heal in a few days; so long as their Master can supply mana they'll heal. This would mean the skill inflicts injuries that [i]can't[/i] be ignored so easily. It's still an advantage if it keeps a Servant at a disadvantage from a minor wound for longer or a major one takes them out.