Even if you don't care about all your data being published in the future, and even if you don't care about getting your data deleted (or door knocked in) because of a random content scanner false positive, you still need to encrypt them.

Many cloud storage services try to understand and then "clean up" file types they understand. If you don't believe me, upload and then download a TB or so of images, documents, music, videos, etc. Then, compare the checksums of the original and restored copies.

On top of that, there are services like Amazon Cloud Drive that have content-type restrictions.

The only reasonable litmus test I've seen in this space is "there is a cryptographic proof that some middle manager didn't screw up my backup".

Unfortunately, that means you need to manage the encryption keys somehow. Cloud storage kind of sucks.