the effectiveness of a characters crouch cancel is based off of a few things: for one, their weight is what determines how long they can CC for. heavier characters sustain less KB from attacks, and thus can CC for longer than lighter characters can. another factor is the quality of the move they will follow up a CC with. characters like captain falcon dont always get much use from CCing because, although relatively heavy, he doesnt really have any moves that are good to follow up with. his dtilt is pretty slow and weak, and doesnt really set up as well as other things do. all of his smashes are quite slow. his grab range is short. his down b can be used for it, but it doesnt really net him all that much reward too often, especially when the opponent is at a low percent.
when applying these concepts to roy, he is relatively lightweight, but his dtilt is quick and ranged enough that it makes for good use in CCing. it also is one of roys best set ups, and is in fact one of the best set ups of that type in the game, period. this means that roy gets a lot of benefit from CCing into his dtilt, as opposed to other characters that dont get as much benefit. he can also CC into dsmash which can be great for a killer if the opponent is at slightly higher percents, and it also comes out a couple frames quicker than dtilt.
