Remember, we have more-or-less FULL EMPLOYMENT at present. Forgetting the fact that might be a few hours a week below the threshold to lose your benefits just to keep the job centre off your back.
The reality is you might say that but I have spoken to a few people who work for a major UK based coffee franchise and they don't know from week-to-week how many hours they are doing because of the lottery system the franchise run for staff rotas. How is that fair? Or the reverse where you are...
Companies are simply getting around the stigma of Zero Hour Contracts by simply putting staff who are effectively full time on 3 hour/week contracts. Not ideal for anyone.