Depending on your threat model this will be very insufficient.

Discs have provisions for bad sectors, they have backup sectors, so if a sector gets too many errors, or has been written to too many times, disks can set aside that sector never to be written to again. So you can have unencrypted data just sitting there ready for somebody to read it

All of the operations indicated in the above post, rely on the file system behaving, and not at the disc level. So superblocks inodes journals and other file system specific data structures could be completely missed. Some file systems store user data inside of these special structures for efficiency purposes such as locality of reference, and time locality.