It won't prevent SQL injection but it makes it trivially easy to use a different password for each site so that when Kickstarter gets hacked you can just change

It won't prevent SQL injection but it makes it trivially easy to use a different password for each site so that when Kickstarter gets hacked you can just change that password. People should use different passwords for different sites anyway but we both know they don't and most people wouldn't be able to handle that.