What are your goals? What do you expect to achieve?
If you want to travel with 100 km/h you can take any car, that will do the trick. If you want to travel 280 km/h, you need a Ferrari, Lotus, or any other “nice cool car”.
So the last one costs more…
So what do YOU expect of the device you are going to buy?
From my understanding (not perfect) for longer point to point links single or dual is fine. If you’re connecting multiple clients or short range clients that have/support multiple antennas/chains the more chains gives more speed/throughput.