Good subject slicks are great as far as rolling resistance more important is aerodynamics. If the bike is going 20MPH the top of the wheel is going 40Mph.
The thinner the tire the smaller the contact patch the more PSI pounds per square inch you can put to the road this translates into traction.
Wet and snow a very thin tire will find the asphalt sooner than a big heavy tread.
Unfortunately we have to ride on the side of the road where all the debris trash sand gravel broken glass ends up. You may be forced off the road in a emergency. This is where tread is needed
This is a 1" tire with 125spi and i have never had a traction issue. rain or snow. but ice is a different story. small patch of ice and your on the ground