Not sure if you are being serious with the question, but if yes, a couple quick answers:

The 10mm Magnum, as pictured above by colt_SAA is a lengthened 10mm Auto cartridge. It was a factory chambering in the IAI (Irwindale Arms, formerly AMT) AutoMag IV pistol. The round never really caught on and brass is scarce but occasionally offered by Starline. There exists no factory ammo that I am aware of, but boutique makers like Underwood or DoubleTap may offer it.

To the second part of the statement...
Ruger recently began offering 10mm chambered Redhawk and GP-100 revolvers. Custom gunsmithers have offered 10mm conversions on GP-100's for many years.

So... cut the 10mm Ruger revolver chambers a bit deeper and now you are 10mm Magnum capable.

It's is definitely the L-O-N-G way around when you take a cartridge designed for a semi-auto and use it in a revolver, but when you are an enthusiast, many things only need be possible and there is no other "necessary" reason.

Benefits: Odd and interesting, which is often a recipe for fun, especially when you are an enthusiast. Also, .40 cal pistol bullets are numerous and plenty and the choices available are wide and many are offered in bulk, all of which are things that (mostly!) can't be said of .410" slugs for the .41 Magnum. You also get ammo swappability in the .40 S&W and 10mm area, not so much in the 10mm Mag unless you have the IAI AutoMag IV. Of course, you can also do moon clips, if your rig is set up for them. Many love them.

Cons: .41 Magnum is certainly plug & play. It would be my thinking that -NOBODY- who plays with 10mm and 10mm Magnum in revolvers would ever suggest that .41 Magnum is silly or useless, but you couldn't expect the same from .41 Magnum fans.

At the end of the day, we are all gun cranks, and that SHOULD pull us all together.