-
Being cold won't do the battery any good. I'd also want a removable battery if it was a bike I was planning to ever lock up. I used to work for a company that hired out a fleet of several hundred e-bikes and the vast majority that were stolen still had the battery attached. Removing the battery when you leave the bike locked up seemingly makes it much less attractive to thieves.
Another benefit is that you can just take the battery off to charge it and leave the rest of the bike in the garage. Maybe not an issue if you have power in there anyway though.
Are integrated batteries a terrible idea in the UK where bike will be stored in an unheated garage?