Why do web users still use password manglers though password is sent in ciphertext

There are many variations of password manglers. An example would be

Hash( user password + secret key + domain site )

During website login authentication , passwords are sent in ciphertext from the client machine to the host machine via SSL/TLS protocol.

The password has already been encrypted , I see no benefit in hashing the encrypted password a second time , what am i missing out ??