Agree that it's absurd if it's just a replacement for normal walking, especially for shorter distances. I assume there will be some carriage type thing or etc.
For longer distances, I actually think it's fine to charge you. If you can't handle the inconvenience of walking, I'm OK with the game saying that your character refuses the inconvenience also, and catches a carriage. I loved the Daggerfall system.
And I do think the disincentive is a good idea. Just a sliiiiiight nudge encouraging you to stay in the game. If you don't want to, you don't have to, but it's good to give you a small material penalty for using a kludge.
I think that's nuts. I have no problem with (and would use) carriages, but one should always be able to open the map, pick a location (reachable on foot), and resume play from there, provided the PC got there without incident.
You are advocating player sufferance because its in line with your personal views on 'role playing' / simulationism; When other players do not all or always ascribe to that. In FO New Vegas, my PC had a broken leg and needed to return to Goodspring... and was limping. There is no justifiable reason to inflict upon the player the tedious and uneventful trek back to the doctor.
Some might erroneously exclaim, "But he had a broken leg! He could not fast travel" ~and this make no amount of sense at all... The PC would be limping all the way back, and it would take 4 times as long... the PC has his own problems to deal with, and the player should not be forced to live them as well... If the PC were attacked along the way, then let the player resume mid-way where the ambush occurred and deal with combat while limping... but once it ends, if they are so inclined, they should be able to have the PC set off for the Doc's on their own once more, and pick up the game when the PC arrives.