My conclusion:
-- Samus' crouch is too high to duck under anything, except maybe zss' mistimed aerials.
-- Walking has the same or greater speed than this trick.
-- The only benefit of this trick is to space dtilt or a bomb, but a bomb used on the ground is generally already used for spacing. So technically, you're spacing a spacing move. Useless.
-- It's walking then using the momentum from the walk to perform a sliding crouch.
-- The distance you slide is pretty small, and not that easy to control (think Zelda's wavedash in melee).
-- Walking is better.
-- Forward slide: left>crouch.
-- Backward slide: right>crouch>left.
Sorry if I ruined anybody's hopes and dreams