Paw helps me compose arbitrary calls faster. It also helps me just keep track of and search API calls really easily, just by searching the request list. I have an API call right there, with the JSON body, and I don't have to pull up the API docs. It's just way better than having a bunch of little shell scripts for these API calls, and better than having a big, ugly, stupid text file full of API calls, because I can execute them, and it really helps in composing them.
It just helps with a lot of little random stuff. Like, if you tell it you're doing a JSON-body form post, and you've got quote marks in there, it'll get those quotes escaped right to get it embedded in the JSON.
If you're a heavy RESTful API user, I'd say just give it a try for a month and see if you feel like it's worth it. I thought it was.
There's command history, and if you're executing calls multiple times in a row and might want to see what changed between them later, the history is great. You can scroll back in your terminal, sure, but you tend to close terminal windows and lose the output. It just keeps everything glued together, it's really much more coherent than trying to throw around a lot of disparate API calls in a terminal with curl (or httpie.)
That being said, I do find it to be complementary to curl | jq. For one, the "keypath" filter in the http exchange pane of Paw doesn't take anything close to a full jq-like syntax. I pretty frequently use the "curl" code generator (it's got an httpie code generator as well, but it doesn't seem that one is as good at shell-quoting edge cases. Not sure who maintains that extension and if it's open-source, but if you love it, you might be able to help fix it if it interferes with your workflow) to copy out the call I composed, and even executed in Paw, so that I can do some jq mangling. (Or i could just copy out the json body if I didn't want to re-execute the call.)
If slinging RESTful API calls is a significant part of your day, you're almost certainly going to find value in something like Paw. It's got a 1 month free trial. I tried it, and didn't really plan to buy it, but a month ended, and I was using it and liked it.