There is a procedure published for the RJ aircraft whixh calls for engines 1 and 4 to be shut down if the APU is usable.
It is only mentioned/used in our procedures with respect to contaminaed runways - less forward thrust.
At some airports, vacating runway to brakes on can be a considerable distance and could over a year save a lot of fuel and brake wear.
The only drawback for the RJ is if the APU fails - not uncommon - as it the only main generator. Engine 3 hydraulic stanbt generator would kick in and nose wheel steering would be lost!