Being comfortable in a language doesn’t mean you will be able to do certain things just by doing them once.
Let’s say you do “welcoming a visitor” in an English class. However good the class is, that does not mean you will be completely comfortable welcoming a visitor when you are actually using the language. It takes experience, it takes vocabulary, it takes time and it takes practice.
But being comfortable in the language is extremely important: it’s the goal. There’s not much point just learning a few phrases, you can do that with a phrase book.
The goal is to speak the language well, and the only way, I believe, this is possible is sufficient exposure to relevant input and content. Speaking becomes only the acid test to see if we are comfortable.