I own two Marksman folding slingshots. One for each hand, I pinch the ammo pouches between my teeth.
Well, not really, I only use one at a time, but I did end up with two, and lots of extra bands.
The folding ones are great because you can stick them in your back pocket, like Dennis the Menace, and pull them out when it's time to play. I've been considering carrying mine as a matter of course.
Marbels are good for hunting squirels and birds. When I was so poor I only ate when I killed something, slingshots kept me and my brothers fed.
The steel ammo or lead sinkers are much more serious, and while maybe not lethal, they will certainly imbed themselves deeply in any butthead trying to cramp your style.
In addition to hunting and holding down the fort, we used to use them for a game like paintball, only we used wads of clay instead of paint. Hurt like heck, and left at least a welt, sometimes a bruise, but back then kids didn't cry to mamma if they got skinned knees while playing outside.
If you wanna get serious, these things are great for shooting broadhead arrows at medium ranges. You can easily take down a raccoon or big dog.
We also used to use a three pronged gig on the end of a real skinny shaft for frogs and fish, sometimes. A turtle too, if you came across one. You know, I could really go for some aligator snapping turtle right now... mmmm, turtle....
I just wish somebody'd make a magnum version with 4 surgical tubing bands for some real firepower.
As far as rate of fire goes, yeah, not like an AR-15, but we used to shoot these things pretty darn quick, loose pockets helped.
A pocket knife and a slingshot, and a kid can have a pretty good time. Older folks too, I guess.
