I like my friends a lot but we don't always agree. With reddit I can read like 5 opinions of a game I want to play and I can instantly feel like "this person doesn't like it and their reasons are similar to things that I don't like too" and make an informed opinion.

The point you make about "professionals don't have time to use Reddit" definitely applies though. /r/synthesizers for example is a great sub if you want to spend thousands on hardware. Not so good for making real music! Although I do feel like there are a lot of Unity game devs on there. Maybe you just need the right community.