The problem is that apps take up little space in comparison to movies and you would likely need to delete an awful lot of them to make any difference.
Even your photo library wouldn't make enough room for most movies but deleting it would likely make a very good start in doing so.
If you are going to get rid of your photos though, make sure you turn iCloud photo library off first (if it's on) otherwise you will delete all your photos from everywhere else too. Another option to deleting the photos would be to optimise them (settings > photos & camera) which means they will take up very little space compared to the space they take now.