1 and 2 will probably make sense to some. It's not something that would overcome my why not.
For 3 the biggest problem with encryption is you introduce a single point of failure, if you lose access to the keys your photos are gone.
On a simpler note I'm a big fan of keeping things as simple as I can. Encryption is not simple. It can be fun to work with and I don't want to ignore that but unless you want to do that for fun I don't think it's worth the complexity.
If you use restic for backups there is not even an option to do it without encryption. Just use something simple you will never forget. Everybody has that password.
For 3 the biggest problem with encryption is you introduce a single point of failure, if you lose access to the keys your photos are gone. On a simpler note I'm a big fan of keeping things as simple as I can. Encryption is not simple. It can be fun to work with and I don't want to ignore that but unless you want to do that for fun I don't think it's worth the complexity.