The secret url link which saves your bitcoin is never a good idea. First you can easily lose it and second, its very easy for a hacker to look at your cache and try to access it without your permission.
It was a smart move for the SatoshiDice guys to move into a user/password authentication system, I was never confident investing in the site with that link - Not sure how the guys with hunderds of BTC on the bankroll slept at night. Will be even better when they have 2FA enabled as well.