I say such app exists because I just read about Speak: https://www.speak.com/blog/speak-announces-27m-series-b-led-...
It's for studying English.
What I don't like about a real tutor is because it's expensive and I have to book in advance. ChaptGPT is free and I can practice with it whenever I want. Besides, ChaptGPT is not a real human so I don't feel embaraced when I made stupid mistake.
And which would you prefer: a cheaper, on-demand version of iTalki (you get matched with someone already online versus booking in advance), or an AI-based app/service that you can chat back-and-forth with whenever you want?
The problem with matching with someone already online is that it might not be the right person. There are tutors that are very good, helpful and inspiring. I don't think I want to talk to random person online. A long term relationship with several tutors are helpful because we know each other better and I'm more comfortable speaking in front of them.
So I would prefer AI > random someone