You still see knitting books that suggest backstitch for just about everything, and I know some fabulous knitters (an elderly English lady, for one) who use nothing else. It works if you keep the stitching line no more than 1/4" wide so you don't get a big, bulky seam.
Personally, I would use it only on shoulder seams, and then only if the yarn or the pattern stitch is very stretchy. It's very firm and helps prevent the shoulder seams from stretching down to your elbows. For most sweaters, the three-needle bind-off is strong, clean and beautiful both inside and out.