OK - not trying to start a flame war, but the term "mouse gun" is a bit unclear to me. Some hold that size is the determining factor where as others use calibre. I am not even going there...
I have two, .32 calibre guns. One is a North American Arms Guardian, and the other is a Walther PP. I really like the Walther (8+1) nine shot capability. It is as accurate as any of my larger frame/larger calibre guns, and is a lot easier to conceal and carry (my opinion). I like it!!! Out to 25 yards it does what it is supposed to - 10 yards or less is pure fun. The gun is a lot more accurate than I am capable of shooting, and I and I am a fairly good shot.
The North American Arms is a close range proposition - sights are not the best, but since a lot of people have them taken off, I don't think they were intended it to be a tack driver. 5-7 yards, 3-4 inch groups are respectable, for a defensive situation.
Why would I want the smaller less accurate gun - peace of mind, when discreet carry is the order of the day. Bottom line, some guns were never intended for competition shooting.