The NPPL appears to be a very valuable licence.
One benefit is that it lasts a lifetime, is easy to keep 'current', and is less likely to be taken off you by medical problems.
I'd imagine if you live in the North then you'd not be very likely to fly abroad anyhow, so the UK-only restriction (apart from reciprocal agreements with certain countires) probably isn't much of a problem. I suppose the thing that would be most missed would be the lack of being able to add an IFR rating - but you can't use IFR for PFA type aircraft as a PPL anyhow...
The PPL does keep more doors open as far as other training and flying abroad, but if your aspirations really do change in the future then up to 10 hours (if I remember right) can be credited towards a PPL anyhow.
As an aside, in a funny way it's a bit like comparing a 'VHF-only' Radiotelephony Licence and a 'full' Radiotelephony Licence. If I had a 'full' RT licence then I probably would not make full use of it.