No, this would not be good for White Mage in that aspect. While it's possible that it might help slightly, the amount of MP you give a party member back always seems to be capped. Now Devotion takes some of my HP and gives it to a party member in MP. For me, Devotion NEVER gives more than 220 MP back to someone, whether I have 400 HP or my usual 880 HP.
So I can't see this being very helpful for a White Mage. UNLESS however, the amount of HP the WHM loses is percentage based, but even in that sense, 80 HP wouldn't dramatically increase that small percentage of your HP anyway.