There’s no real need to stitch images together for 35mm unless you’re using a low megapixel camera (I’d say under ~20mp). For larger formats, it still probably isn’t necessary under about 24mp unless you want to make a large print. I do stitch my medium format images though and I use a 20mp DSLR. But my rationale is I would rather stitch than adjust the height of my camera to fit the full medium format negative in the frame. Call me lazy.
Re: quality of DSLR scanning to a flatbed such as the V8xx or dedicated scanners like the Plustek, quality can be better depending on your setup, but will almost certainly be significantly quicker than either of the other options which are very slow and IMO tedious due to needing to deal with cut strips and swapping them out constantly. Plus the individual scan time for each negative with a scanner vs digitizing with a camera is significantly longer.