The term "casual player" is a loaded term in our community. It definitely brings about a certain image in a Magic player's mind: a Commander or Cube enthusiast who loves durdly six-drops and other "bad" cards.
Outside of Magic, though, the term "casual gamer" means something entirely different. A casual gamer can be your grandma occasionally playing Wii Sports, or a middle-schooler playing Candy Crush, or a college student putting in an hour a week on his roommate's console. In each case, "casual" tends to denote a lack of time, commitment, and money to gaming as a hobby.
How does that apply to what Magic players usually termed casual players? The Commander crowd in my hometown is at the LGS almost every night. A bunch of them play with all-foil decks. They spend years upgrading and perfecting these decks. There's certainly no lack of time, money, or commitment.
Not only do these "casual players" commit more time and money to this hobby than one might expect someone who is casual to do, but "casual" formats like Commander single-handedly drive the prices of cards like Chromatic Lantern, which see no play in any other formats at all, but still fetch foil prices of nearly $20.
Especially considering the fact that many use the term disparagingly, it seems questionable to call these highly committed players "casual." I've been playing a lot of the Dark Souls series over the last few months and have recently started watching some streams. Streamers tend toward one of two styles: speed runs and challenge runs.
Speed runs are just what they sound like: an attempt to beat the game in as little time as possible. Challenge runs involve specific restrictions—keeping a torch burning throughout the entire game, using a specific (and often weak) weapon, or downloading a mod that adds some extra challenge.
We can draw a parallel to Magic from this. Speed runners are like tournament players: looking to optimize a strategy and use it to its best effect. Challenge runners are like Commander players: adding some additional rules and some extra challenges to make the game more involving and enjoyable. Although each group has its own set of goals, tendencies, and priorities, it's hard to say that one is more dedicated to the game than the other.
The true casual players in Magic are the ones you've never met. They're the ones who buy a precon and never update it. The ones who buy a pack every other time they go to Target but never trade, sell, or buy individual cards. They're the ones who play like this:
So be nice to Commander and Cube players. They're just as committed to this game as the tournament grinders—they just have different priorities. Maybe a term other that "casual" is in order.