A few design engineers will assign a meaningful label to every net on a schematic. Then, when laying out the board they only need to hover the cursor over a trace to discover that it is, e.g., “RAM_Addr3” or “Bandlimited_Audio” or “Ext_Current_Sense+” or some other significant node in the schematic. The mnemonics can be VERY helpful when laying out a board, as well as debugging or troubleshooting a board after assembly. These names are also persistent. If you modify a schematic and create a new netlist using KiCAD’s assigned net names, you may discover that “Net-(D2-Pad1)” has been renamed to something else, such as “Net-(C5-Pad2)”.
On the other hand . . . creating unique, meaningful, net names for every net in a design takes some time. Displaying all of the labels creates visual clutter on the schematic. And, a poorly aimed keystroke can create a connection between nets that should NOT be connected.