They are too small and delicate and don’t connected solidly and ‘grasp’ firmly enough. Over the last year they have also worn to a shocking degree on a top spec 2017 15” model. There wasn’t enough friction in the first place and now there’s none.

I work with a professional touring musician and we’ve reverted to his 2015 model for stage use because wobbly poor connectors that have to be gaffer taped to the chassis are not fun.

That said, I have seen a badly tuned Funktion One PA vibrate out a USB A connector from a MBP port in just a few seconds...