In the last two years, I have developed a serious love of 10mm. This has largely been due to me diving into reloading head first. I only started late December of last year and I now load 4 cartridges and will likely add at least two more this year.
The bullet weights available along with the large variety of velocities that can be loaded to with 10mm make it a very versatile cartridge. Self defense, large animal protection, and even small game hunting with a good shot are possible with 10mm, though "large" animal defense has its limits.
As far as I'm concerned it can do anything 9mm, 40 S&W, 45 acp, and 357 magnum or 357 sig can do. The only advantage that any of theses common cartridges has is some can be crammed in a smaller gun, which I don't care about, and more 9mm will fit in the same size gun.
I've debated ditching my 45s and 9mms and just shooting 10mm of different loadings. However, I like variety, and want to pick up a 10mm with adjustable sights before doing this so I can influence POA/POI.
If I didn't load my own, 10mm wouldn't be a thing for me. Too expensive.