Sonoff switch question

Hello together,

hope its ok to post a link to ebay. (

Do I understand it correctly that i can use those switches and „relais“ without the Sonoff RF Base and connect it directly to the wifi?

My plan is to put the relais in my livingroom lamps and 3d print a spacer for my normal wall switch to fit the sonoff wall switch over it. So everybody can

switch on the light with the wall switch or I can turn it on and off with HA?

Regards Tim