In the UK, people do not normally consider that there is a need to use winter tyres. UK winters are pretty mild, UK roads are assumed to be treated and cleared and it is accepted that, if there is black ice on the road, you are supposed to have a crash.
In Germany, the winters are a lot harsher and it is normal to fit winter tyres for some part of the year. Of course, you are not forced to fit them but, if you do not and then get into difficulties or have an accident, you will not find much sympathy.
I'd suggest that, in the event of an accident on snow or ice, any car with summer or all year tyres will be deemed to be the one at fault.
If you decide to get winter tyres, you will see, in the autumn that the accessory shops have offers of a set of wheels and tyres. Normally, the wheels will be cheap steel ones which is not bad either as that will keep your nice alloys free of salt.
If you have a common car, it's worth looking out for a set offered for sale privately as you can save a fair amount of money that way.