So I am running around with a wand of warding +3 and a wand of warding +2 on a gladiator file. It is a useful wand, but is it really the top-tier wand that some people on the internet seem to say it is? The Greater Sentries can be killed, and they even lose health by firing. I could see them being OP if they did not cost health to attack. But the way they are now, if you want them to survive, at least at deeper floors, you have to feed them charges to try and maintain their health. You could have spent those turns directly attacking the enemy instead.

Is there something that I am missing on how best to use the wand of warding? What are the best strategies to take advantage of it?