I made an effort to learn Dutch for around 6 months of last year. Although it's a well known as a language, it's only spoken natively by around 20 million(ish), so isn't massively useful outside of the Netherlands and Belgium, among a few other places in the world. My first language is English. I just wanted a second language under my belt and I enjoy spending time in the Netherlands. The problem with learning Dutch is, most people (that I came across at least) in the Netherlands are already fluent in English and from my experience it seemed like they'd much rather just speak to you in English. So to actually speak Dutch there, it's important to be clear that you don't want to converse in English and that you're trying to improve your skills. It was really important to me that I'd speak a bit of Dutch every day, ideally to native speakers. This requires a bit of effort (as I live and spend most of my time in England), but it's suprising how easy it is to either find Dutch people here to speak to and also online.
It benefited me in the sense that I ended up making some new friends out of it and had a lot of fun just learning (or trying to learn) a second language. I think learning a new language like this can open up some doors and can help you meet a lot of new interesting people you'd perhaps not have met otherwise. I'd love to pick it up again next year. So we'll see.