Today, a single sealed Alpha starter deck might go for $15,000 to $30,000 or even higher at auction, depending on its condition, the sealing, and the sellers reputation
What pushes this into very good territory is the dream scenario of tap four creatures, kill your planeswalker and loot four cards
If its a permanent card, put it into your hand
Besides its art, Belle, Hidden Archer is also a great emerald card thanks to its gameplay mechanics
Card discarding like this is a bit dangerous because you can cause your opponents to draw into better cards, but if you have additional on draw or discard triggers then it's definitely worthwhile, and of course you could cycle this or reanimate and sacrifice it repeatedly
You and that player each create an X/X green Treefolk creature token