In a typical rocket the payload is the most expensive thing, followed by the engines, and then the rest of the rocket and the fuel. Shaving costs off the engine

In a typical rocket the payload is the most expensive thing, followed by the engines, and then the rest of the rocket and the fuel. Shaving costs off the engines is well worth it, but not if it sacrifices reliability. Maybe they have a model in mind where it works. If you use dozens of engines like SpaceX's Starship you can tolerate more engine issues. Of maybe they want to launch really cheap payloads on inexpensive rockets. But in the parameters of traditional rocket design, QA on your engines is one of the last things you want to save money on.