I installed Devuan using this CD ISO file:

https://files.devuan.org/devuan_jessie_beta/devuan_jessie_1.0.0-beta_i386_CD.iso

During installation, all needed packages were downloaded via the network connection. As far as I could tell, the installer did not use any of the packages included on the CD.

I also attempted an installation using this DVD ISO file:

https://files.devuan.org/devuan_jessie_beta/devuan_jessie_1.0.0-beta_amd64_DVD.iso

I observed the same behavior, and when I disabled the network connection the installation failed.

Others have observed the same faulty behavior. See:

https://talk.devuan.org/t/sharing-devuan-via-torrent/270