Some bricks are way too small, so not being zoomed in could look bad
A 1x1 with no zoom makes it's width and height in the 20s, so comparing that to the default 1x1 icon...


It looks bad, but if you do zoom in enough that you get a nice close-up of the brick but not too much that it goes outside your window, you can cut that out and resize it to get an icon with smoothing instead of the aliased look the original has


So with smaller bricks, it's suggested that you zoom in, although, if you want to go as far as copying the aliased look of the icons, you can type $Pref::player::CurrentFOV = 54; into the console and then hold in your zoom key and type the brick icon command


The point is you're still resampling the image. With Blender I can just render at the size I want and it will be visually nearly perfect.
But that can be more time consuming, can't it?