Agreed. If you get a bad draw and Destiny is lucky, he will destroy you using these things. I only lost to him once, but that was when he hatched an Elite Phase Dragon and I mutated one of his Powered creatures into a 12/12 dragon with Steal.
It's a very nice card, but not really worth building a deck around, simply due to the fact that you might get a Spark just as likely as you'll get a Ruby Dragon. It's great for getting huge creatures out very cheaply and quickly, though.