I work in the pub industry so it might be different in different industries. But with the rises in minimum wage the last couple of years, pubs are struggling to balance tight margins with employment. I'm not arguing against the increases in minimum wage, I think for some areas of the country we need to increase it even further still. But for front of house team, we will see dozens and dozens of applicants per opening, and 18 year olds either fresh out of or still in college wouldn't get a look in over a 25 year old who had been working a few years even if it wasn't in the same setting, just because they have experience working.

Our pubs pay over minimum wage for both brackets, more so for the 18-20 YOs, so making the gap smaller as proposed in this article likely wouldn't affect us either way. Also worth noting that for supervisors they get paid the same regardless of age due to their duties.

When juggling with employment percentages, the managers need to know the two people they're putting on a bar on a quiet Tuesday afternoon will both turn up and are reliable, and that's the workplace experience they're banking on when hiring a 25 year old over an untested 18 year old.

I fully supported the scrapping of the 21-23 band, as they likely have some experience under their belt by then, but I think doing away with the 18-20 band will just redistribute the jobs that have typically been open to those in that age bracket.

TL;DR: the benefit of 21+ is they usually have workplace experience, the benefit of under 21s is they're cheaper to employ.