someone will leak the system prompt for Duolingo and thats it - all their moat is just a single git leak away.
you cannot build a moat with LLMs, so there is no value in using any service that is wrapper around the chatpgt
you cannot build a moat with LLMs, so there is no value in using any service that is wrapper around the chatpgt
For what it's worth, I also stopped using Duolingo when the human forums closed. I often found as much value in the forums as in the actual course. And like GP, the hardest part was relinquishing my nearly 1000 day streak.