I always forget about NPS because they’re awful and I hate them.NPS are still the most challenging and as a matter of fact some are still impossible.
Other than a handful like suncorals and dendros most in this hobby can not keep most NPS corals.
There are some in the hobby that could but really do not want the challenge or have the time required.
The biggest issue is feeding food almost 24/7. That is the challenge and then maintaining nutrient levels low enough.
that’s not true. They’re awesome. You are right, by far the most difficult as the constant need for food AND appropriate laminar flow to deliver the food while maintaining excellent water conditions is hard.