I would not buy a camera with coating issues only because I buy for the long term. I buy used gear in excellent condition and keep it.
If I was on a budget and just wanted something to run 120 film through while I test the MF waters, coating defects wouldn't be an issue. I doubt a beginner would notice. The sheer image size/quality difference from 35mm would be an eye-opener.
I used to use my Dad's 35mm Ciro rangefinder from the 1950s. I always swore it had great optics, and they were indeed good for a low-budget camera. When the shutter died for the final time, I took a close look at the lens, and it looked like a Brillo pad had been used to clean it. The last pictures it made were as good as any others it made during its lifespan.