They have a nasty habit of coming loose,they are a pain when loading a trailer with hives because you cannot stack the hives tight together,unless having the ratchet at the top,then you have to remove each one to put the crown board and roof on,they jam and clog up,they corrode,they take far to long to strap hives with,all in all i personally hate the things,just plain inefficient,and over complicated to do a very simple job, and i know of no other commercial beekeepers,(least ways not round these parts), who use them,including the biggest one in the country, for the very same reasons.
Left some of these objects on some hives in an out apairy several years ago,before i knew better,had to cut them all off,corroded solid.