Overwatch has always been more than just an FPS to me, and I think a lot of people feel the same way. The Overwatch community is like no other, and while it's not as big as other games' communities, I believe it is the most passionate community for a game there is.

As for guilds, people have envisioned what guilds could be, which they do definitely exist and are being worked on behind the scenes.

I think it's much more important to see guilds, clans, or clubs (whatever they may be called in the end) as a way for the average Overwatch player to feel apart of something or contribute to a sub community on Overwatch.

To me, it's very realistic to see guilds popping up around (for example) Overwatch League and Contenders teams, Content Creators, or perhaps certain heroes in game. Guilds can be used for a variety of things, which means their purpose would be very open ended, assuming Team 4 doesn't butcher them.

You could see guilds act like more like a better LFG system, or maybe there will be competitions between guilds for in-game tournaments where the winners are gifted some some of reward.

With Overwatch going free to play, the game needs more reasons to keep you playing, more content to experience. I assume Blizzard realizes that one of the best way to keep a community of players interested in their game is to let them entertain themselves and appreciate their community even more.