Inti doesn't have any built-in resiliency to removal, but he does only cost 2 mana, which means you can reliably recast him a few times per game, which puts him roughly on par with the other resilient options in my opinion
The attacked player will get the poison counters at the same time they take normal combat damage, with no window for any kind of response
The creature that returns is a whole new object without any relation to its previous existence
It once saw real Standard play, and it continues to appear in Commander as a political engine or a low-cost superfriends piece
Titan Cards emailed me when it was back in stock, dispatch and delivery was really quick
To mitigate those risks, most decks will want to stick to three or fewer Spacecraft while ensuring a high enough creature count to station them reliably