All characters before 5D's world come with their ace monsters for free. Even the characters from other series added after 5D's came continue to give their ace monsters for free. Stardust Dragon is a UR in a large box, the ultimate pulling difficulty. It's been since September and I still can't get the one single copy of this card that I need. It's bizarre.
The difference is that cards like Black Rose Dragon and Stardust Dragon are extremely powerful, competitive cards. Most of the ace monsters you do get for free (barring Jinzo and Lava Golem) are either very basic, or outright bad. You can't really compare them. Even the remaining "better" freebies like Ultimate Tyranno suck compared to a card like Ancient Fairy Dragon.