As I said I don't claim to be a great/good tuner so sure it could just be my job. But... coming from my racer, when her ski is through Snowglide she can tell before skiing its THAT much sharper and it lasts longer. Another data point - in a regional race in a different age group than my daughter where the GS course is literally boiler plate (it flashed freeze when temp drop from +3-5degC to -25degC overnight), the results were... the top racers all had their skis tuned via machine. One the the "usual top 5" racers in this group all season was 3-5 seconds behind; on a 40-50sec course.
Not saying machine is better but just sharing what I experienced and heard. And of course, there's the reality of time savings...
Yea, you need the sharpest for a race course. I know some racers prefer a hanger on their base edges from the side work.
I hope you realize I was just playing with you here. No dissing at all. You need to do what works for your little racer.