The Hidden Purpose of Parked Domains: What Every Website Owner Needs to Know
It can also be an effective way to collect emails from potential customers interested in your brand so you can notify them when you launch.
For example, some domains display a minimal page with a launch message, while others include a logo and preview content.

Redirect from secondary to primary domains
Parked domains can also protect your brand.
What if your main site is example.com, but somebody else (potentially a competitor) picks up the domain example.net? This can create brand confusion and likely dilute your authority in the long run.