Having just come back from Hockenheim with my racing license, I can tell you that driving a manual car very fast is much harder and more demanding than doing the same with an automatic. That's precisely why I drive a manual: it's more challenging and makes me learn more about race driving techniques, not to mention controlling the car. It demands of me to be an ever better driver. I have to be at least twice as good as other participants with automatics. I like that.
You can get into a slide easily by disengaging the clutch temporarily. Few dual clutch cars can do this e.g. Porsche GT3. You also can do heel-toe downshift without unbalancing the car's weight distribution, if you do it right. Newer cars blip the throttle for you so you don't miss it, but that's kind of missing the point.
I drive both a manual and an older (mid 2000s, 5 gears) automatic CVT. The CVT always seems to get me annoyed as if shifts very conservatively. When going up a slope it feels like the engine is having a hard time. Or it's upshifting in the middle of an overtake at 70 kmh when the gearbox is not in 5th. Always makes me switch to manual in those situations. I've also driven a DSG which works great until you have to drive down a mountain road with tight curbs.