High explosives (like C4) are more commonly used in blasting or cutting operations where the intent is to shock the material but leave it in place. Controlled implosions, underground blasting, dropping bridges, that sort of thing.
Low explosives (like TNT) tend to move a lot of material out of the way. So, quarrying operations, clearing ditches, making big holes. Intent is to displace material.
Of course if you leave 3000 tons of it laying about it doesnt really matter which it is.
