That seller is either eating $4 or buying a lot of Clone Shippers to get them at a discount.
One possible reason not to use them is they're kinda bulky, so require a bigger box for multiple clone orders.
I received some clones in January and all the plastic wrapped around the roots did not prevent shock, they took an extra week to start growing. If shipping in cold weather I recommend a 40-hour heat pack, the same ones used when shipping reptiles.
I sent a message and my seller left me a positive review. This was Magic G3n3tics, solid guy, nice crosses, gear about to drop on Neptune.