A great choice for anyone who loves the tribal experience
We've learned a lot over the years about what does and doesn't work with new players, so when designers had to take less optimal cards to teach, it was never ideal
If I were you, I'd build the entire deck around this excellent Mardu commanders ultimate using proliferate synergies and the like
Every time you play a wimpy rush character like Queen of Hearts, Impulsive Ruler or Stitch, Little Rocket, the Talisman will let you replace them
This drastically speeds up the clock for opponents, especially if you have these in play simultaneously
Once Brotherhood Spy's ability has resolved, removing the legendary Assassin (or Assassins) you control from the battlefield or causing them to lose the legendary supertype or Assassin subtype won't cause Brotherhood Spy's ability to stop applying for that turn