Pros
Looks great on the resume that you have some government experience. Can learn a bit on how the department you intern for works. Potential to network. Remote internship which means a lot of flexibility. Most people in the Bureau I was in was friendly.
Cons
Unpaid and remote. The government workers are a mix of contract and full-time employees but they are all as slow as Trump and Biden debating on TV. The entire internship lasted one year and felt like a joke. A countless bunch of useless meetings with little real assigned tasks. No opportunity to actually develop skills or work on projects and once the internship ended, they kicked us off the slack and didn't even say thank you or goodbye. After a year I still kept getting the weekly ECA meeting email links which is a very concerning security risk for them, I had to manually request them to stop sending me it.