As explained countless times Digital Voice DOES NOT USE WIFI.
Rather than being rude and patronising like some who should know better....
Yes, basically the Smart Hub 2 has it's own DECT base unit built-in if you like, so the BT Essentials or Advanced Digital handset will connect directly to the Smart Hub after pairing without using the Hub's WiFi.
So I have the WiFi turned OFF in the BT Smart Hub along (with other configuration changes) and just use the Smart Hub to pass all the incoming internet traffic to my router directly. So in effect, the Smart Hub is used for Digital Voice and nothing more than passing the internet traffic to my router.
1) So I have a large DECT amplified phone that is itself a base station and this has a separate remote handset as part of the kit. This amplified phone is plugged into the Smart Hub 2 via the old generic BT phone cord.
2) Secondly, I have an Advanced BT Digital Handset that is paired directly to the BT Smart Hub.
3) Thirdly, I have a Panasonic DECT Base unit, that has 4 remote handsets. I use a BT Digital Voice Adapter that the Panasonic base station plugs into and the adapter is paired to the BT Smart Hub.
So as you can see I have phones well covered in the house!
One observation I will make - If I answer a call on the Amplified Phone, I don't get caller ID on the display and I cannot transfer calls internally to the other handsets. It's not an issue for me as the BT Digital Handset and the Panasonic phones all display caller ID perfectly. I only have the amplified unit for a family member who is heard of hearing.