ChatGPT 4 is a great assistant, I find it indispensable... I use it on my phone and computer but would like it in a dedicated device.
Privacy? Yeah it's not great, but that's mitigated by OpenAI focusing the product hard on areas that don't really need privacy.
I do think these tools can be private - but to get there we need more RAM on our computers and phones, and it needs to be expensive high bandwidth RAM, which costs a fortune right now. A lot of research is being done to reduce memory requirements and more manufacturing capacity for memory is being ramped up.