I have a lot of qualms with Threads, such as Thread device internet access through TBRs that do not allow you to disable NAT64 (or even worse, getting globally routable IPv6 addresses in Thread 1.4), but complaining that people have to buy another device is not one.
People are far more likely to have a TBR already than an IKEA Zigbee Hub. And even if they hadn't, they could get any other TBR/Matter Server besides IKEAs. So it's not a great way of selling smart home hubs.
[1] https://appleinsider.com/articles/24/09/18/apple-enables-dir...