Buy these if you're done experimenting with an ideal set up, and you think you've found it.
Then you can mark all necessary rods, stands and rack pipes with memo clamps.
The goal is to be able to take everything down and build it up exactly the same again.
Of course the placement of memo's not only helps putting clamps on their exact spot every time again, but also in the right angle.
The added advantage of these is that they are an extra security for the actual clamp or tightening nuts for stands.
Especially when it comes to vertical appliances that will always be able to clamp with the original nut, but the extra memo clamp leaves out the necessity to screw the actual clamp/stand-nut ridiculously tight with pliers when you just want to be sure.
So even when not used as a memo, their other function can be to add extra security for clamps and tightening nuts for especially vertical usage.
These hinged clamps are handy for situations when a set up is already build and you don't want to break it down to attach non-hinged memo clamps, or when your set up changes a lot.
It's top material, but nonetheless: too expensive for what it's worth.
That's the only reason why it misses a star.