Tig, I don't think its so much a softer compound, just one that doesn't harden as much when cold. That and the snipes for getting heat in. If it was simply a softer compound, on hot days I'd expect wear to be catastrophic.
I'm not against winter tyres - although I have enough trouble finding summers that work - if I had a spare set of rims and a spare £300, I'd probably slap a set on in the winter if it was a good winter. Storing wheels and tyres is a PITA, due to size and sunlight issues. In reality, rarely in the UK do we get the weather to warrant the expenditure, storage and hassle. The other problem (aside from having 3 cars) is my insurance co insists I inform them if I put on winters, and when I take them off again, and each time request an admin fee
Why would that matter if the size, speed and load rating are identical?...........
They specify it in the smallprint
Then your insurance company is terrible. I didnt change my tyres last year or this year (due to a variety of domestic reasons), but the years before that, I simple added on a winter tyre change between Nov and March, with no added premium.