Just my $.02, but I don't own any long arms or handguns for which ammo is even remotely difficult to find. If I can't walk into a local store and find what I need, the caliber loses my interest.
When I wanted a different style carbine (versus .223/5.56) I looked at the Beowulf, Blackout, etc. But with ammo extremely pricey and not readily available, I went with a .308 and have no regrets. Same with my handguns--9mm, .45acp, .38pl.
Again, just my opinion--10mm may be absolutely everywhere in your area. But in my neck of the woods, I've never seen a box for sale on a shelf.