I disagree. Javascript cryptography can provide real security, it's just important to keep in mind what is being secured, and where the vulnerabilities are. Currently, js crypto is vulnerable in that its difficult to verify that the js a browser is running is the intented code.

Every day, millions of people are sending sensitive data over very insecure channels like email and DropBox because secure tools like PGP are to difficult for them or their friends to use. Clearly some security is better than none, as long as the limitations are known.