It makes it so that whenever the enchanted player draws a card, they lose two life and you gain two life
Returning to Sower being a creature you can get repeat uses through bounce spells, cast it at instant speed with things like Aether Vial and easily protect it with effects like Kira or Spellskite
The second reason I think it makes Magic better is that it disrupts the expected flow of the game, it mixes it up and allows situations where turn two things are happening on turn one
There are others, including prize cards like Get Your Game On! and some old Match Winner Prize Cards like Meteo the Matchless that technically only have a TCG printing
Generally, you only want to use Powerstone tokens in dedicated artifact decks, as otherwise they'll be useless tokens more often than not
Not only do these special Evolutions have fantastic and powerful art renditions of your favorites, but the Japanese lettering on the design is a nice touch