The implicit assumption here is that you are giving up your use of the overhead in exchange for early boarding, which is… I guess somewhat preferable? I can’t really see why it’s any better to get on the plane early if you don’t need to make use of the overhead space.

I don’t want to start another thread where people volunteer to add themselves to my ignore list, but if one were to take advantage of this and then go on to put their smaller item in the overhead anyway, negating the entire purpose, I’d be.. nonplussed.