Others can cost more...but it may be that you are paying for "something else"...just as important. But at some companies...IWC, UN, SEIKO, Rolex, Omega...
You get engineering quality:
You are looking at views of the BALANCE spring, the pendulum of a grandfather's clock.
It swings the balance wheel, seen in the first picture, back and forth 28,800 times a min.
365 days a year.
Yes...it IS the heart.
Cheap mechanical watches will not have the cleanliness and total dedication to conformity.
And a good piece...will last 300 years without a service...using today's oils.
This one...will last 10,000 years. Easily.