I didn't say it's a good idea, it's awful, just pointing it out though.

Well, does it? Even if you crack it you don't have the correct casing. So you don't have the original password. Of course doesn't help if every other website converts to lower case too.

But if you use bcrypt you can partially compensate by using a higher work factor.

> Well, does it? Even if you crack it you don't have the correct casing.

The 'correct casing' is any member of the set of all permutations of cases. So you both do, don't, and do not care.