I have been seriously looking at this one from iDevices that goes into the wall. I haven't tried it yet, but like the built in look way better then those ones that just cover an outlet.
I think he's referring to the iDevices in wall Homekit outlet: https://www.amazon.com/iDevices-Wall-Outlet-Monitoring-Independent/dp/B06Y46XDS2/ref=sr_1_1_sspa?ie=UTF8&qid=1511061631&sr=8-1-spons&ppw=fresh&keywords=idevices+wall+outlet&dpID=41e1DlvlCeL&preST=_SX300_QL70_&dpSrc=srch
Not the wall switch.
You can replace the outlet with a Homekit outlet like this one: https://www.amazon.com/gp/product/B06Y46XDS2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 for a cleaner look.
Or just use a Homekit smart plug.
If you are looking for cheap then this is not for you: https://www.amazon.com/iDevices-Wall-Outlet-Monitoring-Independent/dp/B06Y46XDS2/ref=mp_s_a_1_3?keywords=iDevices+Wall+Outlet+Apple+HomeKit&qid=1669674108&sr=8-3
iDevices has this product:https://www.amazon.com/iDevices-Wall-Outlet-Monitoring-Independent/dp/B06Y46XDS2/ref=sr_1_2?ie=UTF8&qid=1511485135&sr=8-2&keywords=idevices+in+wall+switch
I have 3 of them and they are very reliable in my setup.