These two options in combination create the S/MIME user experience for OpenPGP where you just send a signed mail and get the key into your keyring.
I need this for GpgOL and we should also add this for KMail.

While auto-key-import might make sense in the default configration "include-key-block" should only be added based on the context. To be symmetric and to allow users to disable it through config "auto-key-import" should be added, too.
"Include key block" only makes sense IMO for Kleopatra file signing, and mail encryption. I recently noticed that e.g. since I put this in my config I included my key into every git commit signature.