Just a nitpick, but Double Chop is superior to Dragon Claw on ScarfChomp and probably all other sets. 80 Base power distributed between 2 hits means that it carries the possibility of breaking a weak Sub and still doing damage.
As far as ScarfChomp goes, everyone has already said it. It will be useful to check the 100 speed crew and below (and lol Randorosu at 101), but basically Garchomp will need it if it wants to go for a late-game sweep. Too many things are faster than it otherwise. Scarf Shandera, the fighting crew, Meloia, various rain sweepers aiming to outrun +speed base 100s, the newly reintroduced Lati twins, and even ScarfTran from last gen. SD Chomp is...too slow these days.
That said, a Choice Band set seems all the more attractive, and it distinguishes itself from Onono by carrying a decent fire move and much more bulk and speed. Just a thought.
Double Chop is too risky with the 10% chance to miss.