Also as an application gets more complex, it may be harder to keep the juggling act of mutable structures going, and keeping them as fast as they were before.

Also as an application gets more complex, it may be harder to keep the juggling act of mutable structures going, and keeping them as fast as they were before. Mutable structures have a tax that you often must pay with complexity. Immutable structures and React’s declarative approach have more of a flat tax, with means complexity and performance are much more predictable.