WhatsApp backups on Android devices are now taking up space on Google Drive, counting towards the storage quota as of the beginning of 2024.
Google Drive is used for backing up WhatsApp on Android devices.

To find out how much storage space WhatsApp is using on your Google account, access the “Storage” tab in the Google One app while using the stable version of WhatsApp for Android.

According to the information provided on the WhatsApp support page:
When deciding to back up your WhatsApp chats on an Android device in the future, the backup will adhere to your Google Account’s storage capacity.
Introduction and release date
The new way of managing WhatsApp for Android app backups in Google Drive storage is being implemented slowly, which means you may not need to pay for extra storage on Google Drive to keep using the service as usual.