The additional Thopter token won't have any abilities the other tokens were created with
Similarly, if The Soul Stone is already harnessed and becomes a copy of something else, it stays harnessed, though it's very likely that won't be relevant until that copy effect ends
Its Coastal Piracy-style ability to draw a card whenever one of your creatures connects is really good for green, making this an EDH staple in any deck that wants to turn creatures sideways and doesn't have easier ways to draw cards
Sabrina buys you some time
When the creatures are imbalanced and the spells are terrible, midrange dominates
Its also about the tactile feel of holding the cards in your hands, seeing the way the light hits them, and exploring the little details