While it’s true that these piers-without-legs can be an advantage in very deep waters or where the bottom is mucky or has large boulders, their length is limited to a very few sections. That’s not a problem where it’s deep because you don’t need a long pier where it’s deep. But if you need a longer pier, it won’t be enough to anchor the pier only at the shore. The first wind would rip that right out.
Whether these piers can really stand up to the spring ice movement is dependent on the size and orientation of the lake. Generally these piers are problematic in larger lakes for this reason. When the ice moves on a larger lake (2-3 miles across) not much will stand in it’s way. Just because the pier will ride on top of the ice as the ice sheet moves beneath it won’t save the pier when mounds and mounds of ice pile up. Manufacturers know the limitations of their piers, but individual dealers may not. A warranty is no guarantee that ice won’t damage your pier. Guarantors simply know that the odds are in their favor and can accept some risk.