Talkiet:
Srsly. Try it. Log into internet banking with your caps lock key on and you'll still be able to log in.
Cheers - N
ASB is also case INsensitive. When prompted, they'll claim it doesn't matter because they have "128 bit encrypitation". Srsly, direct quote. Including misspelling.
On the actual topic though, the email is legitimate. Westpac contracts out their marketing communications to AffinityID who own eid.co.nz.