I suppose that for many people that want to practice a language while learning it, the easier thing to write, would be about the things just done, the things familiar to the mind at that moment ... after writing for a while, that becomes a journal.
And writing a journal in Esperanto is not unusual at all ... at least among people that speak Esperanto, as testified by the one found by Greensleeves.
I found interesting the opinions given about Esperanto, without even trying to Google the word "Esperanto". Google would have pointed to about 60 million occurrences of the word Esperanto in the web. That doesn't count the pages written in Esperanto without mentioning the word, neither the pages written about Esperanto in languages that spell Esperanto in a different way or using different alphabets.
Esperanto was published in 1887, 123 years ago. Most of this time, the use of Esperanto was growing, without counting the periods of both World Wars. During the government of Stalin, Hitler, and other "nationalistic" liders, many Esperanto speakers were sent to Siberia, and or killed, just because they always tried to communicate with people from other countries.
There is a vast library of Esperanto works: books, magazines, web pages, blogs, pod casts, videos. You can find thousands of them in the web, for free. You may start at this page:
Resources to learn and use Esperanto (400 links)
http://esperantofre.com/edu/iloj01a.htmEsperanto is a living language, spoken in at least half of the countries of the world.
Get to know Esperanto ... you will be surprised with the results.