Maybe I'm missing your point. You don't lose the ability to get a new card quickly with Coin (i.e., Coin gets stolen, cancel cards and Amex will send a new one)

Maybe I'm missing your point. You don't lose the ability to get a new card quickly with Coin (i.e., Coin gets stolen, cancel cards and Amex will send a new one), you just don't gain the ability to get a replacement Coin.