Not dying for longer means more turns, which means more opportunities to draw cards and take over the game
If a card doesn't specifically use the word win, there's no winning outcome, so a cards like Two-Headed Giant won't ever trigger a payoff like Zndrsplt, Eye of Wisdom
It was so heavily played that it warped metagames
If that ability triggers, you must choose a legal target if one is available
Most planeswalkers take turns to reach their full potential, but the flying + counters mode on Elspeth can kill your opponent the turn you cast it without lessening its ability to be a long-term advantage engine
Efficient flying Dragons are almost always must-haves as late-game finishers, and Realm-Scorcher Hellkite has a few extra tricks to make it even better