With huge bins like that 2 plants is fine. BUT!!!!
The drawbacks are that it's a really inefficient waste of light until they are really big. You should start in SMALL pots and keep them there until they are almost rootbound. If you start a plant in a pot that's too big, it will just grow lots of roots and not really be growing leaves the way you would like to see.
Roots don't strangle each other. They just compete for nutes. I frequently flower 2 plants in one 3 gallon pail if I am cramped for space, or the plants are on the small side. You have to be twice as careful with watering and feeding!