Depending on the tournament, you can get a general well rounded sense of what's going on though. Some Overwatch streams are bad though, where they switch constantly from character to character. It's a headache to constantly reorient yourself since the action can be hectic.

When it comes to Overwatch though, I'd rather just watch the top streamers for insights into playstyles rather than the tourney scene. I don't follow the pros enough, and it's tough following the action if it's not a bird's eye view style.