HomeKit Network Technology Pros and Cons:
has a very large range
requires considerably more power than Bluetooth or Thread
generally speaking, Wi-Fi is more expensive to manufacture
relatively speaking, Wi-Fi has high latency --in other words sending an "on" command to a device and seeing that device turn on would always be slower over Wi-Fi than a protocol designed for low latency, like Thread
Wi-Fi networks are highly susceptible to interference
Wi-Fi networks are harder to create and mange
not designed to keep hundreds of devices connected
requires much less power than Wi-Fi
has a much more limited range
not designed for more than a handful of devices at once
can have a relatively high latency because most Bluetooth devices are in "low power" mode and have to wake up to respond; also, in a typical HomeKit network Bluetooth commands are routed through a hub
require much less power than Wi-Fi
devices create a mesh network with themselves, thus extending its range, which is a major advantage over Bluetooth.
additionally, the mesh network is configured automatically and can automatically adjust to devices being added and removed.
Thread devices also have a lower latency when compared to Bluetooth and Wi-Fi (low latency means that they respond very quickly to commands)
designed to handle hundreds of devices
HomePods, HomePod minis, and AppleTVs can all act as hubs and can all extend Bluetooth, within their Bluetooth range.
HomePod minis and AppleTV 4Ks are also Thread Border Routers, and integrate your Thread network with your home network and also help create and extend a Thread network's range.
Bridges will continue to exist, both as HomeKit Bridges and Matter Bridges to connect legacy and proprietary devices to our chosen platforms
Thread vs Matter
Thread is a wireless network transport, similar to Bluetooth and Wi-Fi.
Matter is an application framework, like HomeKit.
HomeKit can run on Bluetooth, Wi-Fi, and Thread networks.
Matter can run on Thread and Wi-Fi (but not Bluetooth—Matter can use Bluetooth for provisioning only)
HomeKit APIs work with Matter and can control Matter devices.