Personally I think pointing out the differences between the two are kind of moot. I would think 95+ of Sparx users go that route for convenience and cost savings, and until manual sharpening provides a much greater than tangible benefit, there’s no need to switch. The average youth and adult player is likely not to notice a discernible difference between the two.
I prefer a manual sharpening because I own my own machine and have been doing it for just under 25 years. But the Sparx owners I know have 3-5 players in the house skating in some fashion 7 days a week. Convenience is king.