I prefer them that way, but I have relatively small tanks. I like many of 1 or 2 species instead of 1-2 of several different fish. My current tanks have guppies and platies together and the other has cherry barbs and blue rams.
I have 1 platy tank, 1 yellow cobra guppy tank, 1 golden white cloud minnow tank, 1 neon tetra/least kili tank, 1 yellow shrimp tank, 1 fire red shrimp tank, 1 crystal shrimp tank, 1 cycled with nothing in it yet tank, so I'm for them. lol.
20g platy, , 2 x 10g shrimp, 3 x 20g shrimp, 7.5g shrimp and 1 great dane/mastiff puppy.