Gear down in the air are pretty worthless, but it does simplify things a little. In addition to getting about 3 or so knots more airspeed for each gear sucked into the belly, it gives you a lot of performance options. Dropping the gear can be another source of drag to add to the propellor, speed brakes and flaps, comes in handy when ATC wants max speed to the FAF, and then you are faced with the go down and slow down dilemma. But also a safety feature. Lose an engine and have to put down in water or a muddy field, leave them up and no flippy. Hard field or pavement, put them down. Encounter moderate or severe turbulence above Va, and drop the gear to slow down, and in some aircraft increase yaw and longitudinal stability. And then the performance envelope. Coming into Salt Lake on an Angel flight in a Mirage one day, ATC had me on the downwind of International at 11,000 feet on the arrival. The norm about 15
Miles up the arrival and 15 back in the conga line. Guess they were appreciative I was flying the Angelflight flag, and asked me if I could see the runway. Sure could. Cleared me to land from
11K on downwind at around 200 knots. Explained to the pax, the sounds of speed brakes and gear, and that we were cleared to land and it would be a steep but safe approach. Power back to 18MP, speed brakes out gear down and a nice smooth downwind/base/final slowing the whole way while descending 2000-2500 fpm, and a stabilized 85 indicated vref on final. Saved a little time, and the pax thought it was pretty cool to get priority over the busses. So the fixed gears are sensible, but do leave a lot of performance on the table.