My Z4 has never failed an MOT (had 8 now), had two advisories, once for old tyres and once for corroded discs. Both were more than 3 years ago and it has had clean MOTs before and after. 31k miles on a ten year old car. Gets a score in the 500s, so around 50%. I don't understand how the data is computed.
If it becomes a 'thing' and people start to take notice of it, it could devalue very very good cars and increase some of those not so good IMO.