If you have teleportation skills, you don't need teleportation tokens.
However there are limits to the number of times you can teleport using your skill per day (*). I believe that tokens allow you to go beyond that limit.
Actually the T5 write-up specifically says "you can teleport a friend twice a day, or more with teleportation tokens".
Another teleportation trick to get around limits is to have your friend follow you (using the follow menu option). If you're following someone who teleports then you get to teleport along with them - for free!
(*) I know for sure that the number of teleports per day to locations you choose from the map are limited, but I'm not sure about whether it's limited if you're teleporting to locations you've bookmarked with your Rock.
If I remember correctly the limits are 3 per game day using the Teleportation skill set and 5 per game day using tokens - able to combined for a total of 8 TPs per game day.