The deeper and wider circumferential grooves on summer tyres mean that water only has to move sideways to the nearest channel and not halfway across the tyre surface in a sideways direction ( the same reason that narrow cycle tyres do not need any tread at all to deal with even very deep water ) you only really find out about aquaplaning if you drive at any appreciable speed into water an inch or more deep, then you will find that you can turn the steering wheel and nothing happens. The dedicated winter tyres like Nokian have self-cleaning grooves ( like tractor and military truck tyres, which is why the Nokians have arrows to show direction of rotation, you have to be careful to mount them on the correct side of the car ) that actually move snow, slush and mud across the tyre and out the sides ( allowing the tyre to dig down to firmer grip ), they also (as you said have said ) have extra sipes to grab drier snow and improve grip, but one of the main secrets of winter tyres is they have a much softer compound ( that actually loses grip above around 7degC ) which is why braking distance for winter tyres in warmer weather is significantly more than summer tyres, summer tyres also have more sturdy tread blocks that resist deformation and shuffling, winter tyres with their intricate tread patterns allow the blocks ( especially when rubber softens above their design temp ) allow too much deformation and instability in the tread. As I said all seasons are neither fish nor fowl and a compromise. I would consider A/S if our cars had pressure sensors built into rims but fortunately I don't have that problem. The main reason I have winters on steel wheels is that I have seen what winter salt can do to alloy wheels ( and how much they cost to get refurbished ), I have also seen how much better steel wheels are at protecting the brakes, and I would not be so bothered about sliding into kerb on icy roads with steel rims as a coat of Hammerite makes them as good as new. Our 'summer' alloys are now cleaned and waxed and forming a multi-story spider home in our garage till after the daffodils have flowered LOL
https://www.tyremen.co.uk/blog/winter-tyres-all-season-tyres-and-summer-what-difference
Proper winter tyres have four times the traction on snow and ice than summer tyres, we live in hilly Shropshire and last year during the beast from the east we were out and about - driving up and down snow covered hills almost as easily as if the roads were dry, the telling thing is we saw some SUV and 4x4 stuck with their wheels spinning - the only other vehicles we saw moving were Land Rover Defenders and tractors.
A brilliant post that, just about sums it up?
My next door neighbour bought has Audi Q3 Quattro, when we had the big lot of snow last winter, he was quite disappointed to not be able to get out of the hollow we have in our close with it, he thought that it would cope.
When we finally got it out, along with their BMW 5 series and Alfa Mito and parked them somewhere that the roads were clear I drove him back in the Jazz up a steep slope that everyone else avoids, he was gobsmacked, that an ordinary little car could do that, because of the tyres and knowing what you are doing!
OK, I have some 'off road' driving experience and done a couple of driver training courses that were well worth it IMO.
The most amazing was in a Range Rover, last generation (L322) V8 Diesel, that vehicle is simply outstanding, it even altered the power steering response when in the mud and rocks setting was selected, it was incredible what that car would do!