Esperanto is interesting
Hi, I am a native Japanese speaker learning Spanish with duolingo. I am impressed how easily I can understand Esperanto with my small knowledge set of Spanish. It is an interesting artificial language.
Must of the root in Esperanto is Latin which Spanish, French, Italian and Portuguese are also based on. So learning some Esperanto will help you learn the Romance languages. Benny Lewis wrote a blog that learning some of this will help you immensely with other languages.
I don't know too much about Esperanto communities but I've heard they exist, there are probably plenty of groups online that speak Esperanto.
If someone doesn't speak a language you know but you want to talk, and you both know Esperanto, it can be useful there too, since Esperanto is easier to learn and use than pretty much any other language. :)
You could read some books in Esperanto, once you become proficient enough to read novels. Project Gutenberg has quite a few, including an Esperanto translation of Robinson Crusoe, and one of The Strange Case of Dr. Jekyll and Mr. Hyde. I imagine there are other resources for finding original literature and media in Esperanto, but there are a few to get you started.