Neo-Siri in iOS 27 removes the need for a lot of this, but before then, if you want to ask a robot about information that is stored in Apple notes, or to send an iMessage, a Mac mini is your only practical option.
It has nothing to do with Macs being especially good at AI. It has everything to do with being one of the last 'cheap' devices being sold with that much unified RAM.
The second is that the puck is heading towards local models. The people running their own 'Claws are usually experimenting running their own services either to save money or to explore the future where 95% of requests are handled on device.