Google services hold some of the most private and confidential information of internet users. Using secondary email for Google accounts is utmost necessary as it ensures you never lose control, and if somehow you do then you can recover it back without much fuss.
Although use of secondary email is optional but Google recommends it because of multiple reasons,
- Secondary email is the safest way to reset/recover the lost password of Google accounts. Other methods are slightly vulnerable to hacks. This also avoids the need of remembering the security question.
- Secondary email account helps Google to communicate when you’re about to run out of space and inform of any unusual activity within your account.
However, with launch of SMS verification by Google, secondary email might lose some importance but it’s still the best way for account verification and password recovery as it keeps the user within the most secure channel.