If nothing else, spending a few days playing with it will give you an idea of what it's good for and if you want to continue, or it'll make it stick in your mind so you can come back to it if you ever need it.
I guess this must be true on places like SF since I see this so often on HN, but almost every single job listing I've seen strictly requires knowledge of a specific tech stack, with the exception of a few internship programs.
But things like TLA+ are way different from even that. The number of programming jobs that will bin you if you don't have TLA+ on your resume has to be like, 5 in the world. Nobody is going to see it on there and be like "we _must_ hire this person!".