No real point in conjecture but there is no real reason ( barring exceptional circumstances ) why anyone should be flying shallow VFR glideslopes in GA aircraft with flaps. A bit of extra height might give you that safety cushion in case of the aircraft going tech on final.
The elephant that might be in the room is a recent thread on here where some folk (at least one who we suspect isn't even a pilot and was subsequently banned) was pushing the idea that everyone should always fly 3 degree approaches....
"that's what PAPIs are for".
This aeroplane appears to have undershot. There could well be a technical reason for that and I'm not saying the accident pilot was using flawed technique. But as a general point, perhaps a look back at that other thread in the light of this tragedy might be educational for those not yet convinced that PAPIs and VASIs (yes, I know there are none at Caernarfon) and 3 degree approaches are not appropriate for light VFR singles except under unusual cirmstances.
I await the AAIB report with interest.