Used as a blunt instrument it can be Nevinyrral's Disk and wipe out the whole board, and if you can show your hand via a small investment you can do it at any time with confidence that nothing on board is likely to be too expensive to take out
It's the difference between a 5/5 Baneslayer Angel for 5 mana and a 6/6 Baneslayer for 4 mana
If that spell's mana value is 5 or greater, create a 4/4 blue and red Elemental creature token
In fact, it more than made up for the fact that neither of us were, at that moment, in a pub
Just having ward isnt going to be enough to get you included in most decks
There's other ways to gain life, of course, including doubling up on Debt to the Deathless or just going infinite with Exquisite Blood + Sanguine Bond, gaining infinite life while your opponents lose infinite life