"He is Marcus."
Translation:Is est Marcus.
Correct me if I'm wrong (I only started learning 6 days ago), but wouldn't est Marcus/Marcus est be what you'd use to generally say "that person is Marcus," whereas Ille/Is est Marcus would be preferable in a context where his gender is important, in order to emphasize that Marcus is a male?
It could be better, except:
If it's a beginner course, in the first lessons, requiring to teach us pronoun.
Hey, I think we are in this case!
If there's the need to disambiguate the person, if it's a "he" or a "she".
Maybe they say "Is est Marcus" because they want to know it's a male (the person doesn't know about the -us ending being masculine).