Why is this 2x the size of mixin-deep?

[Heath Morrison]

Is there any functional difference between,

  // 3.5Kb
  result = mergeDeep(obj1, obj2)

  // 1.1Kb
  result = mixinDeep({}, obj1, obj2)

[Jon Schlinkert]

From the readme:

[Heath Morrison]

@jonschlinkert I saw that, but it doesn't answer my question. I believe the examples I wrote above demonstrate how you can use either library to accomplish the same behavior as mergeDeep, but mixinDeep is 1/3 the size.

Is there any functional difference between those two lines I wrote?