There were 2-3 days in March that produced that horrendous snow. I was driving to the Lakes and it was some of the worst conditions I've had to drive in, but even on small, hilly, country roads I still managed in summer tyres.
Don't get me wrong it was one of those journeys where I'd wished I'd not been out, but it was a short period of freak weather.
I was up in Aviemore in Feb this year and the roads were fine. Don't know where you are, but you don't get much worse snow than there.
No way would I say that your video is typical of weather from last November to this March.
I'm not saying that winter tyres aren't useful in some parts of the country - but to say that we get conditions like your video for more than a week or two at the most is a bit of an exaggeration.
Even the winter of 3-4 years ago, which was the most snow I've seen in Scotland in my lifetime, combined with some the coldest temperatures, only prevented me from getting to work for a few days - but that was due to road closures rather than my choice of tyres.
Winter tyres are almost never a necessity in this country (unless as already mentioned, your drive is particularly hilly). But there are times when they are not just convenient, but also a lot safer than simply 'getting by' with summer tyres. Suggesting that's the case for 5 months of the year though......!!
(and would you want to?)