Same thinking as others: get one if you’re in a Supercharger wasteland or driving through one, otherwise it is unnecessary. These wastelands are rapidly becoming extinct, at least in the US.
That said, at least two Tesla Owners Clubs near me have loaner units for their membership. If you can avail yourself of something like that, you’ll save the cost of the adapter, won’t need to carry the cumbersome thing about all the time, and you’ll have a bunch of new and wonderful friends.