The most devastating part of the weapon is the punishing potential to steal permanents, including those fetch lands your opponent wants to crack
The difference with Reject Imperfection is the prerequisite to get the additional effect
With Jayemdae Tome, a slower pace and mass removal cards like Wrath of God or even Balance, which was unrestricted for an unbelievable amount of time, you could sit in the Tower and all but dare your opponent to try and do significant damage to you without overextending while the game swung inevitably towards one in which your deck would dominate
Once you got it, however, it proved itself a bit more useful than Articuno, with a higher Max CP and a slightly more useful type
Enchanted creature gets +2/+2 and cant become suspected
Evasion matters a lot in Commander, and thus Kykar may wind up being the better leader after we play around with the build some and seek to include more cards