I skated the easy streets in a slippery indoor and they felt pretty normal....It's a good question though because they are suppose to a softer wheel that still slides, where an SPF is a harder wheel that sticks....they didn't help me but didn't make things worse....
It's me getting more OCD, but lately I put in a tiny bit of coconut oil around where the bearing sits in the wheel, just so it's exactly where it should be. Often if you just use the press or use your axel, the bearing can be a bit off, if you ever skate a cored wheel, I at least like how they pop in perfectly. The bit of lubricant makes the bearing to in easier which is prolly better for it too. It's just bad news because a bit more grease attracts dirt.....
Carry on....