For example, if there are two +1/+1 counters on Aerith Gainsborough and it gets three -1/-1 counters, you'll put two +1/+1 counters on each legendary creature you control when Aerith Gainsborough's third ability resolves
The only sacrifice you make is that Teferi is untapping those lands at the end of your turn, so you can't immediately reuse them, but that's okay
Triton is most effective in decks that feature a high count of locations
The deck then adds powerful madness spells including Kitchen Imp (2/2 flying hast for 1 mana with madness), Fiery Temper (burn), and Alms of the Vein (drain) to capitalize on your discard/loot abilities
Golden Egg is one of the cheapest dedicated Food producers and does so while also giving a bit of fixing (which helps splash or enable Adamant)
Being a mythic and never getting a reprint outside of Secret Lair and The List means this card has held its price well