Recently in Teams migration there was an error coming up only for posts in the "General" channel but everything else was in other channels. So the idea is...
- be able to export team channel messages with SG PowerShell as csv file
- import messages to new channel from csv or similar

In this case there are hundreds of Teams that was migrated successfully except the posts in "General" for those teams. This could also be handy for some kind of teams merge etc.