Its the same reason that mechanics like mill and lifegain are so rarely successful as a dedicated strategy
They include mechanics that would be impossible to include in a standard MTG set
If the copied creature is copying something else, then Kimahri becomes a copy of whatever that creature is copying, with the listed exceptions
Magic: The Gathering Marvels Spider-Man Collector Booster includes: 15 Magic: The Gathering cards
It's one of those 'selfish' minions Black often gets, and the flavour does work for a 'foul' familiar -- instead of being undyingly loyal to its summoner, it just stops short at being willing to take a hit for its master
I feel like this is a deck that will be fun to tinker with over the years as better creatures come out and there will never really be a solution. Neyith is just fun, replaces your fighters with cards, and gave us a commander that cares about something we didnt quite have a commander for