Don’t worry about where it’s going to lead. If you’re interested in it right now, then follow that interest and walk the path to its end. Once you’ve learned what you needed to learn, the path will end, your interest will return to something else, and you’ll be on your merry way.
The truth is, you never know when or how a certain skill will prove valuable. But I can say with 100 percent certainty that any skill I have acquired out of genuine interest (I’m not talking about being forced to learn geometry as a high school student) has led me down a good path.