Frankly, it may very well be KISS because the other options were so much more complex. Or they said that if we put speed of light to constant to make it simple,

Frankly, it may very well be KISS because the other options were so much more complex. Or they said that if we put speed of light to constant to make it simple, there were so many unforeseen edge cases because of it. The devil is in the details, perhaps?