As a user I don't care whose fault is it. I want my laptop to go to sleep when I close the lid; I want it to stay asleep while the lid is closed; I want it to wake when I open the lid. Only macs seem to be able to do that consistently; I'd be glad to be proven wrong, but over the past decade I haven't found a counterexample yet.
This can be enabled or disabled under the System Settings > Battery > Options > Wake for network access (Always / Power adapter / Never). Or possibly the phone registers it as connected for a while after it sends its last packet?
Dell latitude laptops sleep very reliably. I have had 4 in a row now since 2007.
Also as a side note, as a user, I agree you don't care whose fault is it, but then this is hacker news where we are interested in whose fault it is.
I don't think that's even true with my m3 mbp16. I haven't tweaked with the power settings but I'm pretty sure it is in a connected sleep state when I close the lid; at least when I'm hotspotting my phone will register it as a connected device.