[johnnyanmac]

>Whether that's good or bad I can't say

I personally see it as good. Why wouldn't I want someone I trust with my hair or pipes to not have something to vouch for them?

It's only a downside if you see cost as the most important thing about all else. The clear consequence is that a trained barber/plumber will require higher compensation to make up for the training, and due to less supply since not everyone will be able to get a license.