Do i need google photos if i have all my photos on my iphone and pay for icloud through apple?

Google Photos is not associated with Apple or iCloud. It is a 3rd party resource where you can upload photos to as a decent backup for your iPhone. I keep my photos in Amazon Photos for the same reason.

Do you need it? No. Will it effect the photos you have on your iPhone or iCloud if you delete Google Photos? No.

But keep in mind that iCloud is not a true backup service. If you sync your photos with iCloud, it is a Syncing Service. This means if you remove a photo on your iPhone, it will be removed for all devices using the same Apple ID, including iCloud.

You might want to consider keeping your Google Photo account as a good backup incase something goes wrong with your iPhone or your iCloud drive.

Somehow, I lost some photos I knew I had taken. I couldn't find them anywhere in Photos. I was, however, able to find them in Google Photos. Storing more important data in more than one place is always a good idea.