Not only does the big manabase shift enable powerful cards like these, it also opens the door for potent sideboard hate cards like Rest in Peace, Stony Silence, or Alpine Moon to help make up for the lack of disruption Slivers can access
When it deals damage to a player you get an additional beginning phase after your combat, giving you the opportunity to untap all your lands, triggering upkeep effects, and letting you draw an additional card.
Final Fantasy VIII The Final Fantasy VIII selections lead off with moody main character Squall, SeeD Mercenary
You can end up with no land all game, or far too much land, so knowing how much is the right amount is essential to building a Magic: The Gathering deck from scratch
Playing around problems (and sometimes dodging land destruction) Another niche use case, but one that does come up: if your opponent points targeted land destruction at your fetch land, you can crack it in response and at least convert it into a real land before it dies
Attacking with Aurelia for the first time each turn lets you untap all your creatures, giving you an extra combat phase afterwards