It's largely an individual style issue too -- some people like the look of natural wood. My father made stuff (benches, bookcases, etc.) and I don't think it ever occurred to him to go through all the hassle of staining and finishing just for appearance -- he just left the wood raw.
When I built my wall of bookcases the idea of staining them did not even occur to me, I just painted them white, which seems to me the most practical and best bang for the buck approach. Looks good, protects, and hides problems.
It's only recently that I've started expending the effort to build stuff well enough to warrant staining, and taken the time to find a staining (aniline dye) and finishing method (wipe on poly) that I can pull off to my satisfaction. To me the smooth glassy feel of the polyurethane finish is very satisfying, as is the feeling of accomplishment when you take something to a high degree of finesse.