One advantage of HomeKit-compatible devices is that, if you wanted to add Home Assistant into the mix, it does make adding devices very easy. I'm not an apple aficionado but some bits of smart kit happened to work with Homekit and I had zero issues. It feels like the kind of thing Matter/Thread promise but they aren't there yet.
From my external perspective, going purely for HomeKit would mean you have less choice in your devices and you'll likely pay more for them. However, I'm sure more knowledgeable people will be along soon.