OpenClaw supports all the mainstream (and free) chat apps like Discord, WhatsApp, Signal, Telegram... None of them requiring a MacOS machine.
Is it a lack of knowledge from the users or do they really value iMessage integration that much?
The relevant questions here are: will the person using this machine also conceivably be wearing a pair of $549 AirPod Max? Or a $399 base Apple Watch? Does that person expect to pay more or less for their largest-screen computing device than their headphones?
Framing that way points toward a $350 price point being a laptop for young children (younger than Apple Watch age, so lower elementary). That's a whole different software experience beyond just the hardware.
My understanding is that the barrier to entry to using iMessage makes iMessage a LOT more secure from spam. If you want to do mass iMessages you have to register as a business with Apple, go through all sorts of checks and attestations, etc.
At any rate, iMessages are a lot more trustworthy than SMS. So being able to spam people via iMessage is very desirable. I recall a few months ago a guy posting his little spam-iMessage-as-a-Service product here on HN. You could build your little iMessage spam army using a bunch of Mac Minis...
Anyone who wanted the OpenClaw use case that is comfortable with Linux probably already has several Linux machines (including a few Raspberry Pis) on-hand.