Because it’s the best place to have a debate with other designers - other places - I’m thinking Linked In, have so much shameless self promotion, that many of the debates (if you can call them that), have little value.
Here, people read and understand the questions and we have honest discussions as opposed to, ‘pick me! me! me! I’m the best!’
I’ve gained so much from being a member here and I often point new designers in the direction of these boards.