Can't swim and can't tp on them is pretty useless along with the addition of sleds, only use would be short travels in between close settlements
I think that may be the point, which I like. It isn't like a typical MMORPG where a mount is just a visual representation of a permanent speed increase. Instead it is a tool which helps you do some things better.
Bags+Horse = Great for local or distant gathering or hunting, downside is that it doesn't cross water or climb steep mountains.
Sleds = Great for heavy moving or extreme volume (with chests), downside is that is is very slow moving.