I think the basic premise is it's more aerodynamic (or hydrodnamic if you prefer). However, I would argue you would want to trip the boundary layer at the head, but maybe that's a little more advanced fluid mechanics theory than you want to get into! Suffice it to say it isn't clear that you would always want the absolute smoothest surface possible. that's why the Fastskin suit have slight ridges akin to a shark's skin.
I think the basic premise is it's more aerodynamic (or hydrodnamic if you prefer). However, I would argue you would want to trip the boundary layer at the head, but maybe that's a little more advanced fluid mechanics theory than you want to get into! Suffice it to say it isn't clear that you would always want the absolute smoothest surface possible. that's why the Fastskin suit have slight ridges akin to a shark's skin.
