The Moon Clip 9mm LCR has a couple things going for it.
Ejection!! The LCR, and all uther 2 inch snubs have a SHORT Ejector Rod. With long cartridges you need to get the muzzle vertical and slap the rod hard to get all the brass out of the cylinder.
The short 9mm takes far less ejector stroke to get out of the cylinder.
Ejection!! With moon clips all 5 rounds are held together which aids in getting all the brass out of the gun. If you short stroke the rod, you can easily grab the cluster and get the cylinder cleared.
Reloading: The LCR does not have the same cylinder spacing as a J Frame. That means you need a 5 Star Turn Knob speed loader for things to go right all the time. The 5 starts are expensive.
Moon Clips are normally reasonably cheap.
California Competition Works makes a J Frame Shoot A Moon moon clip belt carrier. It works with 9mm as well as 38 Moon Clips. I have a 442 Pro moon clip, and I have a couple J Frame Shoot A Moon belt carriers.
I have a 625, 610, a 686 and a 442 all cut for moon clips. I have also owned an SP101 in 9mm. Any one who doesn't think a moon clip reload beats a speed loader reload needs more time off the couch, and at the range.
Just my 2 cents
Bob R