Maybe it is not popular because it has lots of downsides.
Games can be dragged out forever. You do not have a short break for the toilet or to go to the kitchen. If the position is difficult you have to move fast, if the position is easy you have lots of time.
It is pretty unclear how much time the game will take. It might be 15 minutes, but it could be several hours.
That time control doesn't solve problems, it creates them.
Also, adding Bronstein delay clocks as an alternative would add tons of confusion with no added benefit.
Maybe it is not popular because it has lots of downsides.
Games can be dragged out forever. You do not have a short break for the toilet or to go to the kitchen. If the position is difficult you have to move fast, if the position is easy you have lots of time.
It is pretty unclear how much time the game will take. It might be 15 minutes, but it could be several hours.
That time control doesn't solve problems, it creates them.
Also, adding Bronstein delay clocks as an alternative would add tons of confusion with no added benefit.

