You can still do the same thing without this node… but it will be pretty tedious (not to mention the node chaos in the editor)! 
But sure it’s a valuable tool for making complex nodes…
Voronoi2D with F0, F1, F2 and F3; and the F1-F0 in the screenshot:
ps. i’m using a patched version with the ‘floor’ function builtedin, thought it’s possible to adapt it with round( value - 0.5 ).