It's so easy to let eggs sit on the counter for a day or two, boil them, blast them in ice water, roll them to break the shells, then just rip the shells off that I don't understand those at all. I'm sure it would take me longer to try to break each egg with the yolk intact.
I boil 18 at a time (I pickle them, so they last for weeks), so there is the problem of storage for those plastic shell things.