Burp cloths and bibs serve similar purposes, yes, but they’re not designed to be used in the same way. Burp cloths are designed to be draped over your shoulder or held against your baby’s chest during burping to catch any spit-up or vomit.
They’re usually much larger and more absorbent than bibs, too. Bibs are designed to be worn around your baby’s neck and catch anything that might come up during feedings.