They look pretty skaty to me! Especially on ice and mud. Or loose gravel on dry hardback corners. I think the main quality of a good gravel tyre is a central ridge unbroken or broken for low rolling resistance on smooth tarmac but with chunky stuff either side for cornering and to dig in on mud/dirt and gravel to give you purchase. The pictures of the Nimbus seem to be purely a road tyre with grooves to whisk away excess surface water, but very little grip. Even my slick gravel kings have tiny ridges throughout for some grip if things get out of hand. Be careful out there!