I used to do quite a bit of travel/street photography with a Minolta Hi-Matic 7s---broadly similar to the Auto S2, though if I remember aright the latter doesn't have a metered manual mode---and it was a terrific camera functionally. The ergonomics clearly weren't those of a Leica or even a Voigtlaender, but for US$30 I didn't expect them to be, and I see no fundamental difference in quality between shots from that camera and shots from a Bessa-R with a Nikkor 50/2 (my usual normal-lens rangefinder kit). I'm sure the Nikkor, or any of a number of good Leitz or Zeiss lenses, would outperform the Rokkor on technical criteria in a lab environment, but who shoots rangefinders in a lab environment?
That summary neglects matters like bokeh and "glow", which are intrinsically subjective and come down to "everyone likes the lenses they like".
With that in mind, I don't see any real problem with using this sort of FLRF for "serious" work, provided the particular lens you have performs to your satisfaction, and it sounds like in this case it does. Weddings give me a bit of pause, though, because normally you'd want some fairly tight portraits, and with a normal lens you'll have to get pretty close to do that. That's a concern with the focal length, though, not the camera system as such.
One thing to worry about is sudden death of the electronics. My first 7s decided one day to quit firing the shutter---it metered, it cocked, it made a little click, but the blades weren't actually opening, and I didn't know that until I got the blank roll back. I think every roll I shot with the second one included an out-of-focus closeup of my eyeball, peering into the lens and saying "Is this thing really firing?"
(I eventually gave the 7s to a friend who's taken up shooting film and seemed like she could use a good camera with an auto mode. I'm travelling less and shooting less 35mm lately, and I'd gotten to where I had more 35mm RFs than I could really use.)
-NT