Price obstacles not withstanding, if I bought an SL or SL2, or even an M camera, those don't really give me any advantage over what I already have. Sure, it gives me access to Leica glass, but I'd essentially be trading one brand ILC for another (much more expensive one). I already like the gear I have, and I have no need or desire to replace an entire fleet of bodies and lenses. And frankly I can adapt Leica glass to my existing cameras if I really wanted.
The Q2, on the other hand, does give me something a bit different. Something that is actually purse sized (I'm a girl, so I don't need pocket sized, but even a Z6 and lens is kind of cumbersome for a purse sometimes), in addition to Leica glass. It would be super convenient for day trips, or even my daily three mile walk, especially since it has the macro feature baked into the lens.
Unfortunately, the price obstacle IS withstanding, and at present there is no way to justify another $5,500 toy (although it has a new price now and I haven't looked to see just what that price is). But maybe someday I'll get a magical inheritance from the sky and I can get something then. Until then, I'll just keep dreaming and using my perfectly lovely Nikon gear.