Suppose I want to keyframe 200 birds or something, taking off two at at time about every second with a bit of randomness. Oh, I want there to be some variation in their colors. And I just realized I want the interpolation on all of them to be linear, not bezier. That's 50+hours of tedious gui work reduced to 4 hours with the API.
In reality/right now, you'd probably use either a particle system, the boids system or just geometry nodes for something like that though, although for earlier versions of Blender your solution would probably be needed.
