I can't speak for everyone, as differing individuals get various things out of covens, but I can tell you what you may get out of it, from my own experiences.
For one, depending on the coven, there is often a very friendly, almost family-like environment. This is very beneficial in that it will provide you with close friends and family, all of whom work towards similar goals and interests. This gives you a bit of networking and lets you get more in-depth in the community.
If you need something, or want help furthering your path- there may be someone in said coven willing to help you out. There may be people with more experience or knowledge than you in that coven, and you can learn quite a bit from said members.
When it comes to the individuals in a coven, many vary in their paths and their practices. This gives you a little bit of exposure to other workings, and may even broaden your own interests and practices. It's a great chance to learn a lot about things you may not be so well-versed in.
As for what a coven entails and what they require, that depends on the coven specifically. It really varies. Best of luck to you. :)
Here's some things you might take a peek at: