Because the less tech savvy people will be confused when the battery starts getting full and charging speed tapers off which will lead to complaints about their 20w charger only providing 3w of power.

**in a non ADHD brain

Stimulates are not as addictive for people suffering from ADHD because it physically effects us differently. If you have ADHD then you have issues with negatively skewed dopamine responses and stimulates help by inhibiting the reuptake of dopamine causing the dopamaturgic response to seem more powerful than what it is (because again I can’t stress this enough the dopamine response does not function correctly) (source)