"The real question then comes to who in the command structure decided to use such group for serving a warrant"

"such group" needs practice similar to how firemen use controlled fires to practice their skills. As such it makes total sense that you would use this as an opportunity to hone the groups skills for a time when the target is much more important.

I've seen cases where the NYPD sends officers overseas to (sorry can't find a link) help with matters that have nothing to do with NYC at all. I assume this has to do with some kind of practice for when they need the same at home.