Fresh cut coral frags can be quite fragile and are nowhere near as hardy as a frag that has been allowed to grow and encrust onto a frag plug. This especially holds true when shipping corals. The fresh cut corals are stressed out and are likely secreting mucus and other things that could easily foul up a bag of saltwater. Not to mention, the frags are far more likely to break loose from their plug because the glue isn’t strong enough to keep them secured if they are bumped or tossed around. When selling corals locally, fresh cut frags are actually better, at least in my opinion. They are stressed from being cut, but the lack of a frag plug allows the new owner to mount the coral however they choose.