For some people the manual coffee grinders are indeed better than electric coffee grinders.
My Grandpa used a manual coffee grinder and would not use an electric one.
He tried the electric one before that I had bought him but he didn't like it and said that his hand crank manual coffee grinder ground the coffee beans better.
He also said that the manual coffee bean grinder made the coffee taste better as well.
I prefer to use the electric coffee grinder myself as it's much faster and easier to use and grinds the coffee beans just fine.
If you're willing to hand crank a coffee grinder then the manual coffee grinder would be okay but if you prefer to make your coffee fast then an electric coffee grinder is better.