If instead you receive an SMS message that ends with @example.net #123456, AutoFill will not offer the code on example.com or in example.com’s associated app.

A million two-factor authentication codes sent via SMS passed through an obscure third-party company. Here's how it happened and why it's a problem. Written by Lance Whitney, Contributor ...

In fact, it has some risks. For example, SMS verification codes can also promote traffic pumping, a common trick used by cyber criminals to make money for each text.