It's still decent, but you'll need to wait until the new years event in order to maximize your profits. At max level without the Black Chocobo Suit, I was able to pull up 1-2 Heavy Metal Plates every day. With the suit it goes to like 2-6 (depending on moonphase, I think).
Spend the time until then raising a custom digging chocobo. Max Rec and Disc, with Burrow and Bore is what I went with.