QDM
I know I often write tongue in cheek but it's
almost true.
It depends on how high you are.
In a 1 mile vis, 6000ft up (funny how many people ask a pilot how many feet is 1 mile - ever thought about that?
) you obviously won't see the surface at all, but it isn't quite IMC because there will be a lot more light above than below.
In more realistic conditions, say 3000m vis (legal for a UK PPL) and 5000ft up, you will see very little of the surface, and no texture if it is water. Again, not quite IMC.
In both above cases it will be hard to keep the wings level and thus hold a heading. You have to relax and treat it like instrument flight. I've done tons of flying like that, under VFR. I recall one 5hr flight right across France which was entirely legally VFR (even, if one wants to be pedantic, in sight of surface) but I hardly saw a thing. With a failed autopilot and thus very tiring.
The standard PPL training solution to poor vis is to fly low, but that has its dangers too of course. Much more so if the poor vis is due to heavy rain, in which case you could be well below MSA and still not see a damn thing.
That is why some level of instrument capability is required. Each to their own of course, and no doubt many (especially of the "traditional" crowd) will jump on me after this, but a pilot who wants to fly real distances does need IFR flying and navigation capability - even if he is legally limited to VFR flight rules.
I've flown 800nm legs across Europe, but even in the UK a lot of summer flying would have been impossible without instrument capability.