The triple crankset has 3 chainrings; and usually has 8 or 9-speeds to offer the rider 24 - 27 gears. This allows the rider to have a wide range of gears.
This crankset has 2 chainrings and a 10, 11, or 12-speed cassette to offer the rider 20 - 24 gears. It weighs less than a triple, and still offers a large gear range. The double crankset also helps reduce drag on the derailleur that can sometimes be found with a triple crankset.
The 1x drivetrain is a fast-growing sensation in cycling. With only 1 chainring on the front of the drivetrain with no derailleur, shifting becomes simpler and you shed weight off your bike. 1x drivetrains are already becoming standard on gravel, cyclocross, and mountain bikes and are even being adapted for road bike use.