Realms are about more than just having a housing space for your character in Magic: Legends, but they are also about that. Indeed, Realms are meant to provide you with a space to craft things and work on larger projects while also giving you a space that is uniquely your own, allowing you to unlock a variety of features familiar to card game veterans such as lands. More lands give you more bonuses for investing in spells of a corresponding color, so forests buff green spells, islands buff blue spells, and so forth.
Players can also use Mana Vaults to earn more Planar Mana for developing their Realms, Arcane Libraries for spell research, and other features like the Cartographer. It’s a central part of the game’s overall progression, and one that will likely be important in the game’s upcoming alpha test, which is already sending out invitations with dates in June. So pretty soon everyone interested gets a chance to explore these systems, hopefully.