Unfortunately, decks with lots of removal can kill this before the first trigger (it dies to Doom Blade), but it can be the nail in the coffin against aggro decks
Amazon & eBay (Market Fluctuations & Deal Hunting) Prices swing wildly based on seller inventory and demand cycles
Some players overlook this trait and put rare cards in their bulk boxes
Rattleclaw Mystic will be 5/4
Triggering off of artifacts as well is a huge deal since it lets you draw cards from Treasures, Clues, etc
But every now and then, you'll look for the collector info at the bottom of a card, see a letter that is absolutely not C, U, R, or M, and wonder what the heck is going on