I love that word conflating.
I'm not confusing the two. It's the particular situation in the UK wrt the airports most likely to benefit from any type of RNAV (GNSS) approach and the current rules.
Those airports that can offer an approach control service and separation of traffic that's in IMC are in many cases not pushing for GPS as they have established navaids that are fit for the purpose of satisfying your b)
Operators wishing to land at an airport without an approach control service or conventional ground based navaids want the airport to, at least, offer an LNAV IAP fo increased accessibility.
The rub is that there isn't a homogeneous (free) radar service across the UK and a lack of airspace of an appropriate class in which to offer separation.
This means that a GA pilot wishing to land at an aerodrome with an RNAV(GNSS) IAP but not much else has to fly most of the procedure (whether IMC or not) in class G - i.e. not a known environment.
The typical T or Y design is quite a big piece in the sky and with the density of aerodromes in this small wet island it means a challenge for the designers.
I don't see it as a mess, I see it as an opportunity for the powers that be to really deliver safety benefits and increased accessibility for all.
SGC