The main reason I prefer to finish to a higher grit, is because it's much easier to touch up on a strop, or cardboard, wood, paper or whatever's available. It's more challenging to maintain a coarse edge this way, without some more aggressive abrasives. Almost never need to return to the stones, unless I actually damage the edge or want to alter the bevel a little bit. If I do let the edge get too dull for the strop, then a few passes on high grit sandpaper will put the bite back in it. High-grit touch-ups remove less metal than coarse-grit touch-ups. Blades will last longer for this reason, if carefully maintained at a higher-grit finish. I'm reminded of this, every time I see an 'older' knife that was obviously taken to a grinder every time it got 'touched up'. That's the extreme example of overkill sharpening, but it illustrates the point.
As with all things sharpening-related, it's all a matter of preference, not need. And regardless of grit, no one actually needs to buy a complex/expensive 'system' of any kind. A system can make learning the process easier or quicker, but it's not necessary. Sharpening is only as complicated as one makes it. The simplest and cheapest of tools (a block of wood, a piece of leather and some sandpaper, for instance) will do fine, if applied thoughtfully.
