I used to mine Litecoin back in 2013/2014 and really believed in the digital silver concept. However I have since changed my mind, and I am glad to be out of it. Especially with the advent of Bitcoin Cash and other competitors, I do not see the purpose of Litecoin other than a testbed for Bitcoin.
The main reason why I see it being succesful is because it was one of the first and is on major exchanges everywhere, and clever marketing by Charlie Lee. But if the price hadn't suddenly spiked back to $30 earlier this year, I don't know if Charlie Lee would at all have resumed working on it. For years it appeared like even he abandoned the project.