A 16:10 screen of the same horizontal resolution is still better due to more height. 16:9 only makes sense for watching movies, but for everything else, 3:2 or 16:10 wipes the floor with it.
I have both 16:9 (3840x2160) and 16:10 (3840x2400) "4K" monitors. And of course, 16:10 is better. More screen estate. It's as simple as that.
Again, for certian things. Not for others. My son has a 16:10 screen and I prefer 16:9 for photo editing.
How is less vertical space better than more in a laptop of the same size? That makes no sense
Well, theoretically a 16:10 screen is better than a 16:9 if they both have the same horizontal size and the same amount of pixels horizontally.
Now, due to the different aspect ratios, those screens never have the same size. I will give an example of how these things are not so simple.
Assume you have a laptop with a 16-inch screen with a 16:10 aspect ratio (similar to the one in the 16-inch MacBook Pro). Assume this screen has a 3840x2400 resolution. Does this screen have more or less real estate than a 4K screen with a 16:9 aspect ratio?
The obvious answer would be that the 16:10 16-inch screen has more real estate due to having a higher resolution and more pixels vertically. But that does not seem too obvious to me.
A 16:10 16-inch display has approximately the same horizontal size as a 16:9 15.6-inch display. If you compare the two of them, the 4K 16:10 16-inch display would be superior, as it has the same pixel density and more pixels vertically than a 4K 16:9 15.6-inch display, therefore having more real estate to work with.
But a 16:10 16-inch display has approximately the same vertical size as a 16:9 17.3-inch display. And now things get interesting. If you use both of them at native resolution, then the 16:10 16-inch display has more real estate than a 16:9 17.3-inch display. But you will probably conclude that images and text look too small at this resolution and that you need scaling.
Perhaps you reach the conclusion that, for images to be of an acceptable size on your 16:10 16-inch screen, you need to scale it to resemble 1920x1200. If you keep exactly the same number of "simulated" pixels vertically, you would have scaling that resembles a 2133x1200 resolution on the 16:9 17.3-inch display. This number may seem odd, so you might want to use something similar such as scaling that resembles 2240x1260 or even 2080x1170. In any of these cases, the 16:9 17.3-inch display will provide more real estate than the 16:10 16-inch display, despite having a slighter lower resolution.
Of course, this would not be the case if the two displays were Full HD. In this case, the 16:10 16-inch display with a 1920x1200 resolution would always have more real estate (and sharpness) than a 16:9 17.3-inch display with a 1920x1080 resolution.
But, the way I see it, when the resolution is high enough and allows flexible scaling, it comes down to personal preference.