Typically displays are low resolution devices (mine, a SpectraView output's 109PPI). So you're not seeing close to the sharpening for output. In theory, a higher resolution display gets you closer. But it's far, far from WYSIWYG (far from say soft proofing, a far more important use of the display IMHO). Further, sharpening that makes a great looking print can still, on any display, look ugly and over sharpened. So I don't see the point of suggesting a 4K display is 'for printing' although it's closer. Close only counts in...... Fill in the blank.