QFIs teach students how to fly. We used to have a centre of excellence known as the Central Flying School which taught QFIs how to teach pure flying skills.
But then It Was Decided that a new spin was to be placed upon this. No-one wanted to go to Valley as they wouldn't 'get a useful qualification' as a TI - and they didn't want to be what was scathingly termed a 'trimmer'. So Senior People changed the rules.....to get themselves out of a hole. Not my words - but those of senior Qualified FLYING instructors of the CFS Exam Wg.
Incidentally, try teaching people who have NEVER been through ANY aptitude testing......