I don't know that the nomenclature is all that important. The primary function of the part is to lock the slide back after the last shot is fired so that the gun can be reloaded easier. It does not mean that it cannot serve as a slide release.
I looked at the instruction manual for my BG 2.0. It describes the loading procedure as inserting a fully loaded magazine into the firearm and retracting and releasing the slide to chamber a round. It then indicates that you can eject the magazine and top off. It does not address a reload from slide lock. I have been using the part, regardless of nomenclature, as a slide release for a loaded magazine for decades for all my semi-autos, whether Colt, Glock, Beretta, Sig, S&W, etc. It is more efficient and saves time.
Whether the part will release the slide with an empty magazine in the gun is a different issue unrelated to the name of the part. My Sig P365 will not do it. I have two BG 2.0s. The one with a lot of rounds through it (as well as the magazines) will release the slide whether the unloaded magazine is in it or not, although it is easier if there is no magazine in the gun. The newer one with the new magazine is still stiff, and it is very hard to release the slide with an empty magazine in the gun. I don't view that as an issue of any importance.