Service connection tool should validate the downloaded content.
When Service Connection Point is offline (No internet) and you need to use the ServiceConnectionTool.exe this process should be as solid as possible.
Had a case where the 1902 update where downloaded and imported to the SCCM 1810. Everything looked good. Installation started and went all the way to Install File step. Installation failed since the initial import did not include all prereq files in the redist -folder.
This could have been avoided if there would be some kind of content validation e.g. after the download or during the import or during the pre-req check.
There are different "manifest..xml" files that contains the information of the needed files and file hashes, so should not be a too difficult to implement. :)