You risk at any time to lose all your cloud photos and videos since Apple may remove them for any reason.
”Apple reserves the right at all times to determine whether Content is appropriate and in compliance with this Agreement, and may prescreen, move, refuse, modify and/or remove Content at any time, without prior notice and in its sole discretion, if such Content is found to be in violation of this Agreement or is otherwise objectionable.”
It is still ONE valid option to store your files, isn’t? I have not checked, but I wouldn’t be surprised if the EULA for OneDrive, Dropbox, Amazon Photos, pCloud, etc. is very similar. Otherwise, as others pointed out: if e.g. your photos are important to you, you should have local duplicates/backups of them.