Unless you do a lot of work with precast panelling, the 'split with gap' tool doesn't really get much use in the office. It is a worth while tool not to forget about though.
I was recently in the middle of documenting a building with internal masonry walls. We decided to run downpipes in the walls, thereforing requiring the masonry wall to stop and start at each downpipe location. Cue the spit with gap tool. Clicking once on the wall creates an automatic gap in the wall to the desired distance entered in the options bar. In our case 200mm for a 150 dp. Revit allows a maximum gap space of 308mm. While the regular split tool with 'delete inner segment' ticked could do the same thing, its more tedious dealing with a small specified distance as accurately.