Ah, I see, I thought the mobile would need to persistently be next to the DECT base. What's basically a long-range Bluetooth headset makes sense, thanks.
Needs to be next to the DECT base only if you want to use the cordless handset on the mobile line. So yes, go about your day with mobile, then when you charge at night, leave it next to the base and carry the DECT around the house.
It is precisely a long-distance Bluetooth headset in phone form factor. The multi-handset, single-base units are very good.
The point is: how do you ensure that you always have a phone on you?