Combine rest spread and default value

Question

I know I can use rest spread to make any number of function arguments available as a named array:

function logArgs(...args) {
  console.log(args);
}

logArgs(1, "a", {});

For specified function parameters, it is also possible to define a default value right in the function signature:

function logA(a = 1) {
  console.log(a);
}

logA();
logA(2);

Question: Why does using both throw a Rest parameter may not have a default initializer error?

function logArgs(...args = [1]) {
  console.log(args);
}

logArgs(1, "a", {});
logArgs();