Absolutely no reason other than the fact it would be so hard to sell. I doubt there is one buyer in a hundred who likes a matte finish so this would really narrow your market. If you really want one just order a cue from a custom builder.
This is one I've got waiting for a shaft.
It used to be a full splice one piece snooker cue.
Now it is a snooker handle
It was finished typically, but only polished lightly.
Customer likes it so it is now a matte finish