don't know if you are UK based or not. In the UK the rules around IFR in class G and UK PPL privileges are unique in the world (to my knowledge) and this helps the IFR/VFR/VMC/IMC what can be logged debate fill pages of forum archives.
For a UK PPL in class G there is almost no operational difference between being IFR or VFR and there are no boxes to tick beyond quadrantal flight levels, if above the TA (and an obscure minimum height over mountains issue).
Filing a class G flight plan gets an equally good ignoring if it is V or I - And I believe a PPL can perfectly legitimately choose either (for Class G flight).
Obviously trying to count good weather class G 'IFR' flying toward your ATPL isn't likely to work.
All of this is irrelevant to the core question of IFR and Night in Permit aircraft.
Irrelevant to the core question of IFR and night in permit acft? Not really, whatever we may think about the capabilities of permit acft the acft itself has to be certificated. And so does the pilot if he wants to log IFR or night time.
There may be no operational difference between flying IFR or VFR in class G, but as I said before, and echoed by I0540 why would you therefore feel the need to say you are IFR?? You certainly can't log the time as IFR (as you agree).
Permit acft are becoming more and more sophisticated in terms of construction and performance. Equally true for avionics systems and their performance. But bjornhall provides a model answer regarding the current process for acft certification as to why things are the way they are.
Oh dear