Some users are moving to local models, I think, because they want to avoid the agent's cost, or they think it'll be more secure (not). The mac mini has unified memory and can dynamically allocate memory to the GPU by stealing from the general RAM pool so you can run large local LLMs without buying a massive (and expensive) GPU.

Easy enough for average Joe to set up. Can run several Chrome tabs. pi cannot

They recommend a Mac Mini because it’s the cheapest device that can access your Apple reminders and iMessage. If you are into that ecosystem obviously.

If you don’t need any of that then any device or small VPS instance will suffice.

What everyone else said, plus the cuteness factor

A Mac allows it to send iMessage and access the Apple ecosystem.

When I tried it out last time, a lot of the features are macOS only. It works on other OS, but not all.