Back in the day there weren't many wide back options. You pieced backs or you used sheets, or you might be able to get typically bleached or unbleached muslin so no/few color or print choices..
Personally, I liked the weight of the sheets better than the thin muslin. It was usually more economical for me to buy sheets than piece the backs from yardage, especially since I had sources for seconds.
My one big caveat is that a white sheet particularly shows every single imperfection of yours and can create its own. Your assembly skill should be high or your ability to deal with flaws on the back (and who looks at the back anyway) should be equally high.
A nice print back hides so many imperfections. I love big bold prints but I often have problems using them except as backs. In the last few years I'm doing more and more piecing of my backs, incorporating otherwise orphan blocks from the front or fabrics that just didn't make in in the front, or other things.