why don't people like helicoiled bolt holes in intakes

I recently worked as an engineering contractor for NASA. We used a lot of aluminum to make stuff that flies on the International Space Station but my main project was a propulsion control system for long range exploration.

EVERY tapped hole in aluminum utilized thread inserts, no exceptions except for super light duty usage.
Not Heli-coil but Keensert style. Many of these were #2 or #4 screws. Everything was built to Mil-spec standards.

Another thing, lock washers are never used. Everything was loc-tited or used locking type fasteners.

GM stopped using lockwashers more than 20 years ago. My engineering manager at a different company around 2000 was a GM retiree and one of the first things he did was eliminate lockwashers. This was for HD off road equipment.

I've adopted these practices in my own junk.