If you have low mana costs, lots of ramp, rocks and reducers, or don't need to cast your commander several times, you can lower the number of lands in your deck
Completely filling a characters Sphere Grid will earn you the achievement Sphere Master, while completing it for every character will give you the Perfect Sphere Master achievement.
Foils are also in high demand by players who want to make their deck as blinged out as possible, so theyre usually 60% to 100% more expensive than the non-foiled version
The two are absolutely comparable, and Fateful Absence is, ironically, sure to stick around in decklists for a long time
One fun advantage they carry into battle, some of the best Halfling commanders partner
way too expensive and like, what Gruul lands