is attack on titan (shingeki no kyojin) episode 79 filler?

Inside Grisha Jaeger's memories, Eren and Zeke watch their father pick up a crying baby Eren. Zeke notes that Grisha looks happy for a man who has lost his previous family and friends, and is resentful of that fact.

He is showing this to Eren in hopes that Eren will understand that his father has brainwashed him into thinking the way he does now. Zeke takes Eren a little further into his father's memories and shows how Grisha uses his profession as a doctor to get close to people in power in order to track down the king and the Founding Titan.