The point of doing this is that it is too hard for a non coordinated group. Getting matched with 5 other people who do not have headsets and so you have no chance of completing even a small percentage of the content is not fun.
I've joined many a MM games and invited everyone to a party so we can community and surely it should still be the option for people who don't have the friends ? I get your point but it's just an extra option that I think should be there for people because it doesn't mess anything up for the people with friends