Long tail/kicks, at the base level, give you more room to sit on slides; a longer/mellower kick will also lessen your krook angles (so you are not so 'boned' in them); they also give the board the length needed for a wide stance/you are tall and riding a short WB, provided the deck has enough fingers of flat.
Take an NHS board, 31.8", 14.18WB, 1/to almost no fingers of flat, steep kicks that are average/short (6.5 tail) to me, that board is going to feel super cramped because the kicks ramp up so fast (fewer fingers) and due to how steep they are, my stance will be more closed by comparison. Even with forged ventures pushing out both WBs, the NHS board, even with a slightly longer WB will feel tighter/more cramped.
Basically, with primitives or this REAL, I get the feeling of a longer WB board but still get the tight flippity feel of the small WB.
It also rings true (in my experience) to what the Proff had to say: steeper/fewer fingers = more power, more fingers/mellower, more finesse.
Given how I skate (fast, big pop, no style), I should be on longer WB/steep boards w/fewer fingers of flat to maximize my pop. That's the only thing I can feel different with this real (or Primitive) boards vs say a DSM board, are my 'straight over shit' flat ground (over boxes, dead bodies or hydrants, etc.) ollies, on a mellower board I have to try harder for height vs just explosive pop and up!