Yeah really great place though not on too many people's list of things to do. I guess Ushuaia is a bit like El Chalten further north, plenty of great scenery easily accessible just a few kms from town.
I think because it's not really on the road to anywhere it's one of those places you go to if you're going to Antarctica, you're doing 'southernmost x,y,z' or you're doing circuits round the continent. While the Ushuaia area does have some attractions it's probably not the first place you would go do them, like look at seals, or a glacier, or even climb mountains because they're not so high, guides can be required and there are few to no approach roads. Those interested in exploration and solitude would certainly have some fun though, nearby Cordillera Darwin was only crossed for the first time last year. I went as I had been travelling south from Villarrica doing various hikes along the way and this sounded from my trekking guide like a good spot for some more. There's also a certain wild mystique about Tierra del Fuego. The reality can be different to expectations but once on the region you feel like you want to see things for yourself.