Communication. Being liable of your action to the Fireteam leader. Promotes players to reach out together to make connections. If matchmaking existed many fewer people would search out clans and make teams that way. Many time Bungie devs have stated that the community is their biggest pride of how this game works.

The point of optional means that you do not have to use it, so I do not get how it can't work, ya no mics mite be an issue but seriously, being forced to search for a fire outside the game is worse, sometimes I wanna just jump right into a game and not have to spend an hour or 2 to search.

That is the problem, it would be too easy, no noob would ever bother searching for mics, so they would end up hitting a ceiling, being unable to pass the first major raid or even some of the harder (post ttk) strikes.

They need to bring in an in game LFG mechanic. Inputting selectable filters to find people in the same category and send invited or join. Now Gally us the mist op weapon and no one needs to use it but a huge amount if players do showing that people will take the easy route. I wouldn't be surprized if it took them do long was because they wanted to test us. Bungie conspiracy theories aside, matchmaking for teamwork focus co-ordinated gameplay is a bad idea unless you know before hand what kind if player you are gonna play with.

If matchmaking was optional your logic would hold true. But until matchmaking is PROVEN TO FAIL this is all based on speculation or other games. How many people would agree that Destiny is similar to "other games"? Answer = few.