The US military has used steel cased ammo in the past, a lot was used in WWII.
The steel case itself isn't really bad for the gun. The biggest problems with steel cased ammo is from either a laquer coating that has been reported to get stuck inside chambers when rapid fire builds up heat, but Wolf has remedied this problem a couple years ago by going to type of powder coating.
The steel used in the steel casing is pretty soft. Remeber, not all steels are equal. The steels used in the construction of your blaster have been surface hardened and are much more durable than ammunition casing steel.
I've heard people theorize about possible peening occouring from chambering many, many steel cased rounds. Nowhere however, have I ever seen anybody offer any proof. Slide and bolt velocities are quite slow when stripping and feeding ammunition resulting in softer impact of parts, and again, because the gun's parts are a stronger breed of steel, unless you are using a junk-drawer-parts-gun I really can't see this happening within the service life round count of the gun.
The biggest problem that lies with the steel cased ammo is that it tends to be very dirty, and in some cases, unpleasant in smell. The purpose of steel cased ammo is to reduce production costs and allow more corners to be cut to maximize margins. Overall consistency of such ammo tends to be quite low when compared to even slightly more expensive ammo. For handgun ranges this may not be so evident, but with rifles it becomes very visible with increased group sizes.
I don't use it simply because I reload. While you can reload steel cases, they are very, very hard on the dies. The other reason is that it's too dirty for more likes, but not much worse than the Winchester white box value pack .45 ACP. I know of one action pistol shooter who picked up a sponsorship from Wolf and has had pretty good things to say about the ammo, including their willingness to work to bring the load down a little so it is closer to power factor without being unnecessarily over.
One very often overlooked attribute of steel cased ammo is that you needn't feel too guilty about leaving it on the range. Over time it will simply rust away.