By modern thinking, it seems odd that it took them so long to adopt this policy. Leaving legitimate workable dies around is "leaving the safety off the gun" if you know what I mean. I suppose one reason they kept 'em about is the great difficulty in making the die in the first place. When one considers the practices of reusing dies, overdating dies, and minting coins in a year other than the date on the coins, I can understand why they had a hard time parting with them.