Looks like it allows the battery management system to learn about the battery on your car.
Effectively it’s what I do using the XC40 normally. At least once a week I run the battery out on a long journey. I don’t plug the car in until late evening and let it charge overnight.
The “battery miles left” indicator on the XC40 can be a bit erratic. I certainly don’t depend on it for any purpose, nor is there any need to of course because the engine kicks in when there’s no battery miles left. After a short journey sometimes I can park with an indicated 18 miles. Get back in and it shows 20 miles but that goes down again very quickly.
I’ve not noticed what Brydo reports but I haven’t consciously looked for degraded performance in cold weather. Climate control is always on and mostly set to 20.
When the weather gets colder I will be preheating while plugged in which helps the range.