Yes, absolutely. I started learning Czech here about two and a half years ago and have reached B2 level. There is nowhere for me to learn Czech in my town and I don’t have anyone else to speak with apart from my teachers.
Having said that I’ve done hours and hours of reading, listening, grammar and vocabulary learning on my own to support my lessons on italki.
Where there’s a will, there’s a way!
I'm also learning English for fun. As I'm not pushed by an urgent need like an exam or a job interview, I go on italki to be with other learners to get a bit more of motivation and fun.
Italki tutors offer one-on-one lessons for those who can afford it, which is an efficient way to learn, especially to practice speaking, The Answers section is also useful thanks to the help of native and advanced speakers. Still, you'll have to work very hard on your own to make improvement, unless you are living/working in a place where your target language is spoken.