G2,  I'll take a stab at this strictly from my point of view. First, what everyone is calling "clips" should really be called magazines. If a bad "person" was trying to to load his/her weapon via clip, it would really, really slow them down if it was a modern civilian semi-automatic weapon such as the AR family (M4/M16).  But for the purists out there, an M1 Garand (think WWII and Korea) a clip would be correct but it only holds 8 rounds. Spend some time on your search engine of choice and you'll see what I mean.
I own two AR type carbines and lots of thirty round magazines. Seldom do I ever fill them to max capacity but when I do, I do. The main reason is I don't want to bother with reloading so often. There are times when I just want to keep up a sustained rate of fire. Mostly this occurs when I am teaching somebody specific shooting techniques and/or circumstances.
If you haven't, take a trip over to the Bear's Den and shoot their Thompson sub-machine gun on semi and full automatic.