There's also the issue of the AI picking up your mistakes and adding more of its own to match the input. When AI Dungeon came out, I recommended it to a friend as a way to practice English, but when she showed me a playthrough, it turned out that the AI had adapted to her writing style full of misspellings and grammar errors, so it probably didn't help at all. (I haven't been able to test your chatbot yet to see whether it suffers from the same problem.)
In general, practicing something allows you to do it with less and less effort until you barely have to think about it at all, but if you're practicing making mistakes , that just means you'll be making mistakes without thinking about it. To get better, you also need to notice your mistakes to change what you're doing accordingly.
So I think a bot that can guess what you were trying to say and can tell you what you should've said instead might be a bit more useful.
In general, practicing something allows you to do it with less and less effort until you barely have to think about it at all, but if you're practicing making mistakes , that just means you'll be making mistakes without thinking about it. To get better, you also need to notice your mistakes to change what you're doing accordingly.
So I think a bot that can guess what you were trying to say and can tell you what you should've said instead might be a bit more useful.