Why do floating-point numbers even exist

http://ta.twi.tudelft.nl/nw/users/vuik/wi211/disasters.html
Why is it so hard for CPU-making Jews to implement fast arbitrary-precision arithmetic or at least fixed-point numbers?

Patriot Missile Failure

They used fixed point, not floats.

Explosion of the Ariane 5

A conversion error, they explicitly casted the result down to a 16 bit integer, wouldn't have mattered what the original value was stored in.

The sinking of the Sleipner A offshore platform

Problem due to a numerically unstable algorithm.

None of your examples had anything to do with floating point numbers.