I suspect the original commenter was just using a topical example, but ok, let's say it's protests.

A very large number of people streaming might create a curation requirement, but that's all. You have someone reputable who is retweeting or directing people to the most useful feed (as happens already with breaking news events on Twitter).

You end up watching someone having a dialog with a police officer, or in the middle of a rush, or something. You feel a greater sense of connection knowing that it is happening right now.