I always have Tor installed and I often use it instead of incognito browser sessions when researching stuff. It's sometimes slow and Cloudflare made it a lot more annoying to use than ~5-10 years ago, but I'm glad it exists.
I'm sure it's still more useful to US interests though, or it wouldn't be funded anymore.
If they don't control most of the nodes in-between they can control all the exit nodes they want. If you connect though 3 Tor nodes, as soon as one of them is not controlled by them they likely can't identify you.
That's not to say that they don't control most of the nodes, and your traffic likely goes through NSA nodes exclusively
The CIA, not the NSA. Tor is a great way for agents deployed abroad to phone home with plausible deniability: "I'm sorry Mr. Chinese Officer, I got homesick and really wanted to watch some BBW porn..."