I guess some of the more particular mechanics say it makes a difference. If the grooves in the tread form arrows, the "arrow" at the top of the tire would point forward, like a tractor tire. The idea is that any water under the tread could move out rather than be forced in under the tread. The tire makers that put arrows on the sidewalls claim it has to do with the weave of the fibers rather than the tread.

Tread on car tires is there to reduce hydroplaning. With the small size of a bicycle contact patch, hydroplaning is not a danger. Less tread would then be better than more tread--look at the tires of a race car.

Different tread designs are mostly there for marketing, especially when it comes to hybrid and comfort bike tires.