I have a eureka mignon - a good, but messy grinder - as much coffee outside the portafilter as in. I also have scales that I’d never used previously. The dosing cup eliminates the mess and allows for an easy weigh in before filling the portafilter.
I tried a dossing funnel but just didn’t work for me.
Honestly, with all the unnecessary things you can buy when you’re into coffee this has been so well worth it.