The developers of Heroic are in regular contact with GOG employees, and they also get a cut from any GOG purchase made through the Heroic client.

When have they not had the full package on GOG?

There really is no difference. For almost all intents and purposes, GOG’s offline installers can be treated the same way as physical CDs of way back then, with one of the only exceptions being that you cannot resell them.

Nowadays the Heroic Games Launcher is the preferred solution for downloading and running GOG games. It’s a community-run project, but officially affiliated with GOG.

The Heroic Games Launcher can download and run GOG games. It’s a community-run project, but officially affiliated with GOG.