One reason for fast travel: You won't discover places, which is apparently a good thing because locations scale to your level and then lock there. May not be fact, but it is common advice on the webs, so I don't go somewhere without an objective.
While Skyrim scales and then lock to your level, I think that only happens when you actually enter that zone. If you don't enter that cave, merely discovering it won't lock its level.
But using wagon does have a problem - while things scale, they do have a minimum level, especially those in the outside world. Go to a place too early and you get your ass handed to you.
When I started my mage, I hired a wagon to go to Winterhold directly after doing a few quests in Whiterun. IIRC I was level 14. When I got the College quest to Saarthal, I couldn't even get to the location alive. On the snowy path I encountered two foes - first, a human named "Scavenger". He was wearing various items looted from a bunch of dead Stormcloak and Imperial soldiers. He quickly turned me into mincemeat with his steel hammer. I reloaded and lured him to the other College student, who is conveniently marked essential. But the next foe is a sabertooth tiger. It killed the student in a single swipe, so I ran back to the Tolfdir (the teacher). I thought Tolfdir would be able to kill it easily. But no, he was killed in three hits. There's absolutely nothing I can do at that level.
I was more annoyed at his assumption that nobody enjoys a Bethesda game without mods, when I have 300 hours at least clocked on oblivion, another 200 on fallout 3 and well, probably about 30 on new vegas (fuck that game).
You can enjoy Beth games without mods, sure; but once you've seen the mods you will never want to go back to vanilla. Starting from Morrowind, then Oblivion and now Skyrim, it is very well established that Beth games are all flawed (and in many aspects, seriously flawed).
I still remember how big a change it is using Rhedd's new head models in Morrowind. Half the polygon count, 100 times prettier. Level scale overhaul mods for Oblivion; and SKSE for Skyrim allowing all other wonderful mods like SkyUI. And countless new questlines and items!
If you play Beth games on consoles you're dumping all that away - a huge pity.