In the right scenario your opponents' could be sacrificing eight or more permanents whenever you swing at them, which - outside of a dedicated treasure or token deck - is going to get very unpleasant very fast
But it's at least worth considering that you could be buying proxies if you are using the cards in a casual environment (READ: NOT A TOURNAMENT), are not trying to pass them off as real, and your friends are OK with it
You don't ladder into your big fancy synchro, you don't turn your extra deck of zodiac monsters face up and place it in a monster zone, etc
Summon a "Kizan", "Mizuho", or "Shinai" as appropriate and exhaust the counters on Battle Shogun
Are they the creepiest Magic: The Gathering cards set in Innistrad
The only place Ive been able to find mint ungraded copies are Japanese auction sites