You still need a light switch where people expect one
The Building Codes require that you do have a functioning light switch in the usual locations. That is not so much for you, they don't care if you can turn your lights on with your Google Glasses... They are a requirement for
- Guests who they don't want getting hurt in the dark
- EMTs so they can work 2-handed while saving your life, without holding a flashlight or delaying care so they can get you out to the ambulance where light is
- Firemen so they can quickly determine if the room is clear
- Police so they can quickly see that your son who got SWATed is holding a gaming mouse, not a gun
Obviously they are not mutually exclusive; with smart switches it does suffice for the wall switch to bepart of the smart-switch ecosystem send an "on command". It just has to work. The wall-switch "on" must easily bring it to a medium light level, what would be bad is if it was stuck at a previous very dim mood-lighting level that can only be changed from your phone.
If you are going to use your phone 99% of the time, a real risk is the batteries running down and you never knowing it. So one option is to install a wired smart switch (controller) and re-task the physical wires to deliver always-on power to the switch.
Don't use unlisted cheap Cheese junk
The item you linked is notable in its lack of a UL listing, or rather a listing from TUV, CSA, UL or some other competent testing lab which operates in Europe. The only thing you see there is a CE mark, which stands for "Chinese Excrement" - seriously it's a voluntary mark which means the manufacturer only claims to comply with certain EU standards. In actual practice, far-east manufacturers stamp it on absolutely everything, so it might as well be bought at a street vendor in Bangkok. The vendor states that proudly... so clearly they are not interested in paying the fee to have TUV or CSA test it, since they know it'll fail.
Well, buy from someone whose stuff actually is tested by an impartial third party.
