Inferno tactics.

Sage, well, that's certainly correct, but I'm talking about the fact that he already had Hellspawn and 96 Imps at that time, which didn't really fit into the strategy. By the way, he could have just as easily converted the Gogs... in my opinion, they were 0.0% useful there.

This is just a discussion on the topic, without any particular connection to a specific game.
Of course, if there is an opportunity to convert Imps (which came with the heroes or from free recruitment) into Demons without being distracted from the main goal, then why not do it.