Audiomaze,
I can't comment on the swarm which is a specific model of bass array, but conceptually bass arrays are much easier to integrate into most listening rooms versus, well almost anything else. If you have the money and space, you can use room treatment, but doing it right, it not easy, and taming deep bass requires large structures or good/lucky use of harmonic traps. If you have a lot of flexibility in placement, very good results are possible with 2, but 4 is going to allow more flexible placement. Careful with subs near mains. If the swarm has reasonable bass management and they are low distortion so you don't get false images, then I would expect they will work well.
I can't comment on the swarm which is a specific model of bass array, but conceptually bass arrays are much easier to integrate into most listening rooms versus, well almost anything else. If you have the money and space, you can use room treatment, but doing it right, it not easy, and taming deep bass requires large structures or good/lucky use of harmonic traps. If you have a lot of flexibility in placement, very good results are possible with 2, but 4 is going to allow more flexible placement. Careful with subs near mains. If the swarm has reasonable bass management and they are low distortion so you don't get false images, then I would expect they will work well.