The code requires all exterior outlets to be of the "in use" variety meaning you have to be able to close the cover over the plug. Here, you snap out the inner panel and bellows expand the cover to meet that need.
Ahh Interesting. My house has the old-school hinged white metal plate with a 15A GFCI. My house is from 2003. I've seen other houses use clear covers which I think are ugly since they're so bulky. I like this since it's low profile. I like the cast aluminum version of the bulky plastic ones for some reason lol.
According to the NEC, all newer exterior outlets must have an "in use" cover. The old snap covers are considered obsolete. And yes the "bubble covers" are fugly.
They may be. But I would recommend replacing it with a "while in use" cover if for anything, to protect the plug end and receptacle while it is being used. There are lots of low profile options if you don't like the bubble cover.