Is this needed for anything? Looks like just the installer unbundled from the .exe file. Maybe would be needed to uninstall cleanly? If it’s not useful at all then the installation process should clean it up.
Yes, these files are required for upgrades and even uninstalls. Windows Installer can’t (or couldn’t) always figure out the upgrades otherwise. I haven’t reviewed the requirement for this in recent versions of Windows, but certainly it was a problem for many years. I don’t plan to make changes to this, given it is working well and the only cost is a bit of disk space.