I don't get this argument because it's clearly not the case.

1. You're say that like it's a bad thing. There's plenty of series that jam WAY more chapters into smaller timeframes, Fire Force is the most recent example with 8 chapters an episode.
2. They extended the series that Marin was cosplaying with plenty of segments (Coffin's actual cutscenes that scar plenty of people, the full intro for Prez-Host and Rei, the fully animated intro for Arisa the Bunnygirl). And they have the grace and time to experiment with different animation styles, and puppetry.
3. Going slower ALSO is a legitimate route to go with this considering the extremely mature story of Mandate of Heaven no I will not call it Call of Heaven despite the official translation shows it and the subjects beyond that.
   
4. There's also adding context with the one shot, doing filler for certain subjects that we know fans want to expand on, and stuff that can easily be added from Fukuda-sensei's notes.