Really? That sounds like an urban legend to me… Take 3.3v to 5v level shifters, I’m sure you can take them out in 99% of projects and it will continue working. Question is for how long and what happens the day the 5v supply runs at max spec’d voltage. Or take ESD diodes, every circuit works great without. Fuse of any type: out. That doesn’t make much sense.
What makes a lot of sense to me is the concept of throwing everything you may need in and then once it’s working figuring out how to simplify. It often means that when one part of the circuit changes 'cause you didn’t really understand the datasheet/requirements/timing/whatnot then other parts don’t have to change 'cause they’re robust and self-contained. And then later once it’s all working you can see redundancies or defenses that are not needed and pull them out.