Someone asked me recently why I'm studying Spanish. I'm not exactly sure. Anyway, who says that learning a language has to be useful? The fact that you enjoy doing it should be enough. I'm learning Hawaiian, and it's not even useful in Hawaii because so few speak it. Enjoyment has its own value. Of course, it's a nice bonus if the language you're learning happens to be useful to know. That's why I encourage people to study Spanish rather than German, even though I love the latter language and am fluent in it. The fact is, in the U.S. you'll get a lot more use out of learning Spanish than you would German.
Even if you live in rural America you'll quickly see the utility of learning Spanish. I can now communicate with Spanish speakers in my area, not fluently of course, but adequately. The people I meet usually really appreciate my efforts because it's not the norm for a non-Latino to bother learning Spanish. Aside from that, I just like the way Spanish sounds. I also find it a useful language in terms of New Testament studies since there's a great revival of learning in Spain these days when it comes to the New Testament. I fell in love with Spain years ago when I was invited by the Greek Department at the University of Madrid to give a lecture on John's Gospel during a summer school session on the Costa del Sol. I had the audacity to give it in Spanish. (You can read it here in case you're interested.) The students loved it. At that time I was living in a very Latino-populated city (Los Angeles). I don't know where you live, but where I live (in Southern Virginia) there are tons of opportunities to interact with Spanish speakers. German is a great language, but the only chance I get to speak it nowadays is when I run into an Amish farmer at Bojangles. I never regret having mastered it. But for most of us, there just isn't any good reason to study it.
Unless you enjoy it!