Benefits of having an iCloud+ account have to be decided by the user.
It should not be thought of as a repository, and indeed Apple markets it for several uses, including iOS backups for restoration (your iPad probably does this too), data for Apps, HomeKit video storage, iCloud Photos, iCloud Drive and a syncing service - among other uses. See What is iCloud+? - Apple Support for more detail.
Regarding your specific query, the photos uploaded to iCloud Photos from your iPad are or can be shared with your other devices and repose in iCloud for safe keeping. You can also choose to have small version of your photos - essentially thumbnail copies - to save space on your device, yet have them available in full size on iCloud for downloading at any time. This is an efficient way to save space on your device.
Because iCloud is a syncing service any edit, change, addition or deletion is transmitted to iCloud and then to all other participating devices. iCloud unifies your content across all your devices.
But if you decide that isn't the way you want to go, then get a couple of external drives and park your content on them. Yes, a couple of drives, because you can't risk having just one copy of content on one drive. If it should fail, and many do in the longer term, you have no other copy. I have some locally stored content on three external drives. This is a benefit of having photos on your iCloud account via the Photos app because if your iPad should fail you can download it again when you set up a replacement device, or upgrade to a new one.
I don't have an iPad so I can't advise on how to get your photos from iCloud to a drive, but I expect it would require a computer to do that and downloaded from iCloud on the web.