Are you sure they are backed up?
The backup allows you to setup WhatsApp on a replacement smartphone with all the chats (and media – photos/videos) you were using before.
This can be necessary in the event of your phone developing a fault or suffering damage, loss or theft.
Usually when installing the software, most set it to backup to their Google drive in the cloud every week (or day if you’re a regular texter like me) – as well on the phone itse
To access this page now, enter your Settings page using the Menu (3 dots in a row on top right hand side on an Android phone) then Chats, then Chat Backup.