The reason might be that we can not easily find people with the same language that we learn or just feeling more comfortable when we read out loud and try to make correct sounds by ourselves.
Definitely not. While reading aloud definitely does help you practice pronunciation, it is not an alternative to having a real conversation. Here's why:
You're simply reading words off a page, meaning that you don't have to actually formulate sentences in your head. In a real conversation, you can't read words off a page; you have to directly answer the question being asked by the other person, and no amount of blind repetition will help you with this unless you have real conversations. Because of this, you won't be able to develop long-term lasting speech fluency unless you have real conversations. At the very least, try to have Skype calls with native speakers.
Just speaking from my personal experience, I find it absolutely helpful to read aloud consistently for a sustained period of time every day (e.g. half a year). I improved my English and Spanish a lot just doing that without having many people to talk to. However you have to read after podcasts etc. where there's good/standard pronunciation to follow.
Also I'd say its effect is greater on pronunciation/intonation than the actual conversation. For the actual conversation skills, you can still practice by yourself. e.g. I just answered TOEFL model questions by myself every day, recorded my answers and analyzed them. In that way my English still improved a lot.