I used char cloth in the distant past. It works well will the old style flint and steel where the flint was real flint and the steel was hard carbon steel.
I don't use char anymore for a few reasons.
First; As I got more skilled I found I could find tinder that worked almost as easily, but without the black carbon mess.
Second; With modern spark rods the spark is hot enough that charring is not really needed.
(One of the points of charring is that it makes the cotton far less able to get damp from the humidity in the air.)
Third; I use lighters almost all the time and the sparkers are simply backup in case all the bics go empty. So to carry a package of charred tinder seems a bit overboard for me.
I think lighting with char is a good skill to learn, and it certainly has a bit of the wow factor built in. It ranks with using a bow drill for wow factor, but I don't carry a bow drill and hearth board to light fires with either.
The only real thing to watch out for is that you are using pure cotton or linen fabric to make char cloth.
A lot of the clothing material now is cotton blended with synthetic fibers and it doesn't always make good char cloth.