This approach was taken not for the emitter spawning purposes, but for ease of creation.
You can make stepless changes by linking one user parameter and emitter. It also makes it easy to visually check the scale of the emitter.
I was tired of editing a bunch of Niagara systems to see changes in user parameters. But if it’s on one system, just uncheck the emitter.
I will continue this approach if there are few negative effects. I personally think this is a convenient approach.