Keep the person next to you from reading your messages
In a meeting or on public transit, having a personal message displayed in full on your lock screen can be awkward. Turning on preview hiding lets you set your phone down without worrying about it.
Strengthen your lock screen itself too
It's also worth reviewing your lock screen password or passcode itself for extra security, on top of hiding notification content.
Frequently Asked Questions
Do notifications still come through if I hide the preview?
Yes, notifications still arrive normally. The lock screen just shows generic text like "New Message" instead of the actual content, which you can only see after unlocking.
Can I hide previews for just one app?
Most devices support per-app settings, so you can hide previews for just your messaging app while leaving other notifications displayed as usual.