I would suggest that whether you train to NPPL syllabus or PPL syllabus, the biggest factor in lessening the risk when flying is YOU.
Both licences mean you have achieved, and been examined to a minimum standard.
It is up to you to then build on that standard and fly in a safe and sensible manner. As pilots we never stop learning.
Just because you hold a particular licecnce does not mean that you will be any safer, it is more to do with your 'airmanship' qualities.
Whatever you choose enjoy it.