Well, it's not obvious to me. In everyday life people would only move short distances and not be spinning or turning under pressure. In traditional koryu - just look around at the various curriculum and method of practice. If they had to move around a lot...they stood up.
Mmmm. Interesting. I suppose it's down to types of training. When you watch for example samurai movies you see choreographed moves but still they are based on expertise. Whether it be azumi or lone wolf but notice there is lots of moving and turning. Real as I call it suwariwaza is or should be no different. All be that high grade.
If I look around at the various koryu or curriculum and methods of practice the many times I will just shake my head unfortunately. Even whilst standing I find many can't turn under pressure and thus to me don't understand some basic motion principles. There is actually a barrier to go through in order to freely do so, a mental barrier. Plus in my experience an incomplete understanding on the whole of the power of basic motions of aikido irrespective of technique. (taisabaki being one such)
Anyway, if doing suwariwaza it starts off nice and slow and technique by technique but eventually is or can be no different to multiple attacks from standing and if I may say so that when 'in the zone' so to speak it becomes easier than when standing, a strange yet illuminating experience.