- When a update for the board is released it makes upgrading the board much easier and quicker if there are no styles added to the board.
- When a new update is released, the themes might have to be updated as well, in order to work on the updated board. Sometimes those themes are not available at the time the board is updated.
- There are a variety of themes available and some people won't care for one theme and care for another.
I hope this explain the plainness of the board.