It's useless in my opinion because it's another form of fast travel
But having said that, I'm getting it for pc, I'm pretty sure someone will mod actual travel.
I would get that mod if it was made.
In responce to what size Solitude and Whiterun are, they seem decently sized. Whiterun looked maybe a bit smaller than the Imperial City in my opinion, but definately larger than the other cities in Oblivion. I didn't get much of a look at Solitude, as when I finished off the guards in the area my time was up and that was it for the day. I'm quite looking forward to discovering it on 11.11.11 though.