In one sense, they are a little pointless (just something fun to do) in another they are very valuable.
Take one of the most active groups on here, the Double Trouble Writing Huddle. In it you write stories with a partner. Seems a bit pointless on the surface, but after writing in there for awhile I realized it gets you to improve your writing because you have o adapt when your partner throws you a twist!
Some other groups are just ways for people who like something to meet. Like the book groups and other culture groups. Those are really for fun.
Others are directed at a specific element of writing, such as Character development. These can be very useful for getting direct and to the point advice on an element you are struggling with. This style of group also gives you a chance to help others if you're strong in that aria.
Hope that answers your question!
