Competitive, yes.
Fun, no.
There's too much happening with those classes that you don't get to enjoy the song
And I would rather not have to play the same song hundreds of times to memorize the placement of every block
Also if you could tell me how to access this mono-only board I would appreciate it
Fun - yes!
If you ask most people here, you'll find we all started off as mono only players. The puzzle characters are often more fun to play, you just need to try them.
You don't need to memorise all the block locations at all. The basic techniques are as follows. These can be built upon to make a more complex play style, which can and is more enjoyable to play.
Pointman - Pick up the higher point blocks and then drop them together to make large matches
Pusher - choose two colours, the most abundant two, send one to the left and one to the right.
Eraser - Collect two colours, erase the most abundant and then when the previous match has disappeared drop the erased blocks.
Clicking on the picture of the mono character on the stats website will filter the board to be mono only.
As 0VERS33R says, you can tag your songs with [as-monoonly] so only mono can play the song, but this will lead you to a different scoreboard to the main one, which might be pretty empty