I didn't read this article but I did decide to use Prolog (which I didn't know prior) for this year's Advent of Code. I ended up solving the first 8 days (so, 16 puzzles) and it was fun.
What I got out of the experience:
1. Intellectual confidence - it's not often that we get to learn not just a new way of doing something but a new paradigm. I am 38, and while I try to challenge myself in all areas of life, how often is something a true mind-bender? The fact that I was able to wrap my head around (some of) the Prolog way of doing things proves to me that I "still got it" and is good exercise for keeping it that way.
2. One specific thing about Prolog is heavy reliance on recursion. I probably "get" recursion better than an average CS grad but this took me to the next level - I will be able to apply it in other languages.
3. There's something about Prolog that makes programing feel like this: a ton of thinking up front, but once you do it, the implementation is bug-free (versus lots of fiddling around in other languages). I guess that's probably true of non-imperative languages in general, but it was a nice change of pace. I am not a full-time programmer anymore (product manager) so for me coding is mainly fun/intellectual and doing it in a way that removes the fiddling is great.
4. Prolog feels very retro, I can't really explain it but it doesn't try to be cool - it's the opposite of say the latest JS framework that is polished to the 9s. Prolog feels more like the cockpit of a fighter jet - sparse and powerful, but you have to know how to use the tools.
5. The community is cool. I found the IRC channel and folks were very generous with their time, though to be fair I asked questions like: "I implemented X like this, is that canonical?" vs "how do I do X?"
6. I am glad to have Prolog in my toolkit. I can imagine problems down the road where logic programming is the best tool and I know I can reach for it now.
Bonus: a few posters in this thread asked about the ROI of learning a retro language given that they could be learning something else. I think it's totally up to you, but looking back on the list above, almost none of the benefits I enjoyed are that I now know Prolog. So I guess you have to pick and chose your challenges, I wouldn't get the same value from learning Fortran77 and I wouldn't expect anyone else to either. Prolog is different enough from whatever else you're doing that it can grow you beyond learning some minute detail of React Hooks (which are great, btw!)