EDIT: Nope, I'm wrong. That would involve sending sensitive data over unencrypted channels, which is a no-go.
Personally I wouldn't care and I'd want that, but that's irrelevant.
Why do you think that? My inbox is plenty of (unsigned) PDFs coming from mx<n°>.<mybank>.eu ...
Headers show they're relayed from <redacted>.internal.<mybank>.eu (private IP included), that spf authentication is ok, but dkim is not even provided.
The GP was talking about encryption: can anyone else involved with any system your email passed through read your intimate financial details?
TLS means in transit interception is not easy and SPF that the address is not spoofed, but without DKIM I'm not able to verify that the content is not forged. As such, for example, my email provider is able to read those emails, and probably to modify them without me noticing.
If something doesn't grant confidentiality, data integrity and authentication, it's not encryption. I don't think TLS alone is enough to qualify an email as an "encrypted channel".
In short, banks sending out PDF statements by email would be dangerous, as sillysaurus3 originally implied.
I'm not trying to argue that it's ok, I'm saying that in my experience bank employees use email for confidential communications.