In my opinion, the "Language Partner" is a good way to practice the convensation skills and communication skills. However, I am confused that it is hard to make it as a long-term relationship. For my experiences, as the time between me and my partner are different or we both have works to do, it is so difficult to keep talking with each other frequently.
So how do you use this function effectively???
It's not effective at all. The only way you can practice on a regular basis is by hiring a tutor or a teacher.