The card is a bit clunkily worded, but in essence, it basically splits each player's creatures into two sides of the battlefield (or the "river")
Eevee Heroes is the most valuable modern Japanese set overall, with two cards from this single set appearing in this top 10 plus Glaceon, Leafeon, and other Eeveelutions commanding $600$725 just outside the list
While I dont personally feel the need to have my Planechase sleeves in a top loader, I do for my AFR Dungeon room oversized cards
You can play extra lands, which already screams ramp and value, but the key here is the delicate balance between discarding, drawing, and keeping your hand hellbent
Raw card investment compounds slippage at both ends