What makes an AI persona feel genuinely useful?

We’re building Samagama AI around a simple question:

When you talk to an AI, what makes it feel like a useful persona instead of just another chatbot?

For us, the answer seems to be a mix of:

- personality fit

- a clear name and identity

- memory

- communication rhythm

- boundaries

- transparency that it is AI

But I’d love to hear how others think about this.

If you were using an AI persona for private conversations, what would matter most to you?