>>If so how does it compare for number of insertions versus 'regular' USB plugs?
Signal integrity would concern me too. Getting USB HS to work right at the maximum allowed cable length is no BS as-is. The diagrams aren't clear enough to show exactly where the two contact layers are or how they're connected, but two divided sets of contacts can kill your SI in a hurry.
As an aside: why, oh why, didn't they make the USB A connector obviously keyed? I'd estimate many lifetimes have collectively been spent trying to shove in perfectly rectangular connectors the wrong way. It should be shaped like a house (a thinner version of the B connector amenable to thin devices) or an arrowhead or something.
Yes. In my experience it's typically done by less technical users who simply haven't noticed that the connector is asymmetrical, so if it's not going in it must just be a tight fit.
If so how does it compare for number of insertions versus 'regular' USB plugs?
Is this a large enough advantage to justify the additional costs?