Privacy Policies are not only a useful legal document to have on every website or app, Privacy Policies are legally required.
Most privacy laws around the world, such as GDPR in the EU, CalOPPA and the new CCPA from USA, Privacy Act in Australia and many others require websites and apps to have a privacy notice. This “privacy notice” is also known as a Privacy Policy.
You need a Privacy Policy whenever you collect personal data from users. Even if you don’t collect information from users directly, such as a through a contact form, you may still be legally required to have a Privacy Policy because your website or app uses third-party libraries that may collect user data.
You need a Privacy Policy if you ask personal data from users through forms (email address, name)
You need a Privacy Policy if you use tools from Google, such as Google Analytics or Google AdWords.
You need a Privacy Policy if you analytics tools, such as Mixpanel, Matomo (Piwik), Simple Analytics.
You need a Privacy Policy if send promotional emails to users (either through your own server or through MailChimp or similar tools).
You need a Privacy Policy if you set up and manage remarketing/retargeting campaigns through Google Tag Manager, Facebook Pixel and similar tools.
In the end, many situations may require you to have a Privacy Policy.