I am afraid that a language exchange is time consuming. I did it “in vivo” with some immigrants and usually after they talked one hour in the local language they weren’t that eager to hear me trying and doing my best to talk in their language. Usually they took an excuse and said that they had to leave.
My italki teachers and tutors are so patient. They focuse on me, sometimes even too much, I rather would hear them telling me what is happening in their life and their country, instead of talking over and over about my family matters.
Professional teachers are more reliable than other language learners.
1. My native language isn't popular, so it's very difficult to even find a possible exchange
2. Teacher and tutors get paid. They show up for an appointment and spend time and energy. With a stranger, you can't be certain.