Y'know, I see an analogy between this and artists' sketchbooks. Some sketchbooks are made with cheap paper, some with what I'll call "medium good," and some with super-high-quality paper.
There's always a need for the cheap paper, even for accomplished artists. For some purposes, only the best paper will do. It depends on what your aims are.
If you come up with a good drawing or watercolor on cheap paper, you can always choose to pull out a sheet of high-quality paper later and make a new version.
It's probably easier to dash off ideas on the cheaper paper, or at least, that's been my experience. Trying to do *everything* on the best paper only isn't a good idea.
The paper can play a big part in the feel (and durability) of the overall piece, but that doesn't mean that it's "wrong" to do studies on cheap paper. Most people can only afford to buy limited amounts of the better stuff, because it's costly. And it's easier to feel OK about making mistakes on the lower-quality paper. (You don't see dollars and cents floating in front of your eyes.)