Here are some of the key characteristics of the different rarities: Common cards are the most basic rarity in the Yu-Gi-Oh
Depending on your decklist and opening hand, this can possibly even be an FTK
The Seat of the Empire can channel for three mana and shoots an attacker or blocker for four damage, which is nice added removal since we don't have that many removal options in the deck
I think another factor is demographics
Mechanically Unusual Fighter: When creating her deck, she gets to choose from four different unique Discipline assets which boost one of her stats and provide her with a powerful ability, which has the cost of forcing her to flip the card over to its "broken" side, disabling it until specific conditions are met to turn it back (or she draws an Elder Sign)
When paired with Lorcana cards that can heal him or any other character with the Support ability (adds their strength to a chosen card when they quest), Olaf can actually become a very powerful card very early on