I would not be so righteous about keeping IFR and VFR watertight.
They are totally separated in the legal sense but e.g. take a nice English summer day: 3000m vis in haze, and for extra measure you are flying across the Channel. And just to make it more interesting the sun is in your face. No horizon, you can't see a bl00dy thing.
But you are 100.000% legal VFR.
On one such "summer" (which I would consider wonderful summer flying weather because low vis doesn't bother me at all) I have seen PPL students do no flying (no x/c, no QXC, no skills tests, just banging yet more stupid circuits) for several months. That sort of thing really shows the futility of being unable to fly in instrument conditions.
Then there is night flight. I don't mean "UK PPL night flight" as 99% of UK PPLs do it which is 31 mins after the official sunset and you quickly bang off the 3 circuits before it gets properly dark. Night flight in the true sense is totally instrument flight. But it is also 100.000% legal VFR.
Go figure, as they say.
Instrument skills, sufficient for aircraft control and navigation in solid IMC, come in really handy. So don't knock someone trying to pick them up, on the grounds that he can't fly legal IFR.