I have this feeling that at some point it will be very advantageous to have personal AI because when you use something that everyone can use the output of this something becomes very low value.
Maybe it will still make sense to have your personal AI in some data center, but on the other hand, there is the trend of governments and mega corps regulating what you can do with your computer. Try going out of the basics, try to do something fun and edge case - it is very likely that your general availability AI will refuse to help you.
when it is your own property, you get the chance to overcome restrictions and develop the thing beyond the average.
As a result, having something that can do things that no other else can do and not having restrictions on what you can do with this thing can become the ultimate superpower.