As far languages go, Esperanto is pretty new - only 130 years old. It's what's called a constructed language (aren't they all), meaning it was artificially devised instead of organically evolved.
If you know Spanish or Latin, you might recognize Esperanto as a cognate to the Spanish esperar, or "to hope". That gives you a clue as to why the language was created - it's named for people who hope. Wikipedia says the language was formed "to foster peace and international understanding." The founder grew up in area sharply divided by language and culture, and he wanted more for the people of the world. He was interested in unity. (This was only a few years prior to The Great War.)
My understanding is that the language's founder wanted Esperanto movement to be just about the language itself and nothing more, but going to bat for peace international understanding is itself a movement So much so that the Nazis and the Soviet Union saw esperantoj (Esperanto speakers) as threats. Tyrants don't like free thought or unity.
I mentioned earlier that I'm learning Esperanto on Duolingo, the popular and free language app. It's a popular language, and a quick internet search will find subreddits, message boards, Instagram accounts, and other examples of people embracing the language.
Whether or not it ever becomes pervasive, I love the idea that millions of people around the world take the time to learn Esperanto based on hope and unity. Maybe it sounds silly, but it's my kind of silly. My kind of people.