Legality depends on the tournament format -- Quick-Draw Dagger can be legal in some formats and banned or restricted in others
It only stands to reason that it is jam-packed with legendary creatures
Even very controlling 18-land decks can just be 18 lands plus several cards that draw or fetch lands for you (Cultivate, Field Trip, Pop Quiz with access to Environmental Sciences, etc.) and skip the 19th land
Particularly for cards like Manga Rares that have a sense of specialness in their appearance itself, they are viewed strongly as collection targets rather than simple cards for gameplay
Cards that make your opponent exile a card from their hand, like Skullcap Snail, wont trigger discard payoffs like Waste Not that care about your opponents discarding cards
Echocasting Symposium You need a half way decent creature to get good results from Echocasting Symposium