There wouldn't be any NDBs in Australia today (and for quite some years now), saving tens of millions of dollars a year in maintenance and upkeep, if some nameless person in Canberra hadn't screwed up royally when writing the GPS specs of the J model Herc.
But that's another story...
Non precision approaches in big aeroplanes are seen to be so incredibly dangerous by some airline managements that they forbid their aircrews from practising them on the line. (Not just NDBs, but VORs and LLZRs as well.) Total exposure to NPAs is once every six months in the sim - unless a line pilot has to do one for real on the line because a precision approach is not available.
I don't know if Thai follow this... shall we say rather remarkable practice. However, when aircrew who aren't allowed to practise have to do an NPA in anger, their management wonders why they sometimes get it wrong.