As I think about it, I guess there probably are more conchs that will bury themselves than those that don't. The larger species usually don't (latissimus, thersites, and the Lambis species), and there are several smaller species that are usually reef-associated, and these don't normally bury themselves. Actually, being in the family Strombidae DOES make them "Strombus Conchs" by definition, since the English name is taken from the family name, and any other "conch" isn't a conch at all.
Cheers,
Don