Hey,
The main benefit group members get by interacting with each other in this way (presuming some sort of work) is "they are learning from each other by sharing multiple perspectives". This is the biggest benefit as by being exposed to multiple perspectives which helps understand if different ways for example; if me and you were in this "group" and I said, well gummies taste better then chocolate because they have more flavour and are tangy and you said whilst that is true, gummies are generally worse for your teeth and oral health, I would understand both sides of an argument or be aware of various facts.
Hope this helps,
Azumayay