The issue there is that arrays aren't first class types in JS, they're just objects with numeric property names.
So if applying an operator to arrays spread the operation across all the elements that way, it would imply that the same should happen generally for all object properties, with whatever weird implications that would entail.
a.foo = 1
b.foo = 'there'
a + b // { foo: '1there' } ?
So if applying an operator to arrays spread the operation across all the elements that way, it would imply that the same should happen generally for all object properties, with whatever weird implications that would entail.