Of course, Dusknoir can only mitigate 130 damage before its own HP expires, and losing it will give your opponent a prize card
Tishana can greatly surprise an opponent when it drops, stopping an ability in its tracks and turning the offending creature into a vanilla until Tishanas Tidebinder leaves the field
Then theres the whole thing of having to keep track of what your Werewolf looks like on its other side, and paying attention to whether or not your opponents play zero or two or more spells in a turn to trigger transformation
Unbeatable Protection for Your Cards The reason to buy Golgari Sleeves is the protection
Why cast a different 9+ mana spell when you can just cast Expropriate and probably win anyway
Its all about counters, meaning you can buff your creatures, deal damage, and proliferate