Well, I've seen the various official mats in videos, seen the blurb:-
"Each player using a character mat receives a special perk: Once per game, at the start of your turn, you may discard a card to draw a card."
So, opinions on that, plus......
It does not say it has to be an official mat.
So, make your own!! Lol.
In my case I'm not bothered by the rule, and can easily make my own mat.
There are various free fan ones already available for downloading, so it's simple enough to print out and laminate.
All the best.
Great Uncle LROG
I don't want a mat.
It takes up space and I have no problem playing the game without one.
As for the special perk, I don't really need that one either.
But if I really found it necessary to replace a card before the game, I think I would do so, whether "allowed" or not.
I'm not too bothered by a mat, but it's something that people can either take or leave, but I don't see the need to have an "official" one to use a rule that most wont need.
If you really wanted to discard a card you really didn't want, you could always trade it at the start of the game with someone else who might find it of use.
All the best.
Great Uncle LROG