i think it depends on conditions. i had studded tires on my mtb and rode on the maybe twice but just like studs on a car they didnt help much in deep loose snow. the rope was a diy i had to do. here's the story: friday was expected snowstorm in the afternoon. fearing i wouldnt be able to get home from work in my mini cooper, i opted to ebike in. that way i could stay off the road and away from traffic. problem was ice! i had one 2.5" knobby tire and put it on the rear (mistake#1) and didnt let enough air out of the front (mistake #2), didnt watch for black ice (mistake #3), fell hard and broke my helmet and bruised some ribs. during the day at work i had to figure something out to get home. lookedat zip ties but they seemed too thin so i got the cord at rite aid at lunch and let a lot more air out of the front ~20 psi. those two fixes plus new snow on top of the ice made for a very nice ride after that! i also got more dialed in how to ride in the snow, putting a foot down near the ground when the bike gets squirrely saved me a few times too. i'd say with the conditions we have now ie. deep snow, the rope is a far better option and it only cost $5. live and learn!
Yeah, I've put about a hundred miles on my radcity this winter since putting on Schwalbe Winter Marathon Plus snow tires (210 studs each 26" tire) last month. It has/they have been pretty good for ice -- which we've had here on roads and paths pretty much constantly for a few weeks now in Wisconsin -- but I've found once you get more than a half inch of dense snow on top of the ice, the studs can't grab anymore, and things turn into quickly more "slalom" than biking (fresh/light snow is not so bad).
My conclusion? You can have a tire that works well in snow (knobby, deep treads) and one that grips relatively well on ice (studs), but you can't have one that does both, at least not well. And sometimes you have to do both, when there is snow on top of hard ice (it is frequently below 0 degrees Fahrenheit here -- when I headed out to work this morning it was -3 degree F)
One thing I will say though about the Radcity in winter that I learned a couple weeks ago, the throttle is a godsend when riding in about 6" of fresh, fairly wet snow!Q It would have been near impossible to resume moving after coming to a stop (which I was doing frequently due to traction issues)