With the others, you just want to play them on curve or if you have another play on curve (such as with [scryfall]Icefeather Aven[/scryfall]) or a chance to blow out your opponent, you choose that
The ability to choose their mana type freely with one card gave players a massive advantage in gameplay, so Dual Lands were extremely popular
Blitzball Captain At the beginning of your end step, if a counter was put on Wakka this turn, put a +1/+1 counter on each other creature you control
Whether its worth your money though, depends on whether this fan-favorite format is one of your favorites, too.
Sometimes itll be letters, sometimes itll be numbers, and other times you may have symbols, or even a combination of the above, to identify which set a card is from in any given TCG