This I meant, use SegWit transactions for low valued transactions only, because they meant to be as anyone can spend and the signature is required only in withness data by certain block versions,
They are not meant as anyonecanspend outputs after the activation because they aren't anyonecanspend outputs after segwit activates.
but this signature in withness data requiremet can be changed with future soft fork and new block version again.
Literally anything can be changed with any kind of fork. This is not a valid argument.