I'd say no because freenet storage depends on popularity of the files.

If nobody is interested to download your files, which they wouldn't be because they are undecryptable blobs, then very soon you will be the only one storing those files, and you have gained nothing from making them available on freenet, but you have wasted your own bandwidth by uploading them.

Also it would be horribly slow as far as storage goes compared to a hard drive.