It's nice and there are use cases for it, but if I ever need something like it, I'll prolly just explain what I want to ChatGPT and tell it what regexp engine I'm using, and it'll give me results I'll paste to regexr.com for tests. The only added value here is that I wouldn't need to think of a prompt, but I've become good at finding nice prompts for programming problems, so directly querying ChatGPT is what I'd go for, personally.

Also, I'm not sure what underlying tech is used, and the only explanations on the tool seems to be a Youtube video, so I didn't look further. I'd like to know more about how it's made, if that's possible and something the author would be ok to share.