Dietary sources of D are almost always insufficient unless you live on only seafood. Sunlight is pretty much the only viable way to get enough D. Probably not diet related.

You don't actually need to read the article. The summary suggests that all that goes in the email is the amount, and the CC to cash@square.com.

Most reputable email services offer sender authentication.

http://en.wikipedia.org/wiki/Email_authentication#Authentication_methods

The bank doesn't need to sign up for a special program a la the OP's suggestion of Interac e-Transfer. It just uses your debit card functionality.

You don't send account info via email. Read the article, or even just the summary more carefully.

You like dealing with physical mail, and cash? Good for you. Most people don't.

There are many systems like this including POP money. The difference AFAICT is that this does not require bank participation.

Virtually everyone has secure communication to their email provider these days. This is no more abusable than password resetting links that are regularly used for sensitive accounts.

Also I'm not sure if you caught that account numbers will not be transferred by mail.

How so?

If this saves more lives than a new treatment for skin-cancer, should we stop working on new treatments for skin cancer?

Using the word "period" at the end of your sentence is asinine, aggressive, and adds nothing to your assertion. Period.