The Key-Frame performs a role of “start and end points of value interpolation” in the animation of the “Key-Frame Animation” and as another important role, “it determines values such as display positions of the parts”.
In case that “A specific value is mandatory in the specific frame”, as an example, if a Key-Frame (using a value desired to be such specific value) is set at the Key-Frame position even mid the course of interpolation, errors per target machine as well as execution environment can be cancelled at the Key-Frame’s position.
However, if too many Key-Frames are placed, the data volume of animation may increase. So, please make the best use of it, considering the balance of application and operational hardware.