It's because of the Mac Mini's unified memory architecture; which is ideal for inference.
It's very difficult to get this much memory on a graphics card.
If you look at the videos and blog posts where they recommend getting a Mac Mini for this are recommending the base model (which comes with just 16GB), precisely because it’s the cheapest Mac that can read your reminders, use iMessage etc. that’s what those using OpenClaw want from the Mini, not its inference capabilities.
On a 64 GB Apple silicon Mac mini you can natively host mid sized and some larger quantised local models .. using Ollama.
For example:
Qwen3-Coder (32B), GLM-4.7 (or GLM-4 Variants), Devstral-24B / Mistral Large (Quantized)