Anthony Robinson at YorkshireBylines [Frost's cabinet role is a slap in the face for the British people] has some useful comments on the significance and consequences of the appointment.

Frost's appointment is not to negotiate future improvements but to ensure there are none. He is not likely to ask for any and, with him as their point of contact, the EU are likewise unlikely to offer any.

The following quip particularly appealed.

Johnson's choice of Brexit minister is full of irony, since the PM sent Frost to Brussels essentially to put an end to rule by unelected bureaucrats. Frost is not only an unelected bureaucrat himself, but now an unelected member of the Cabinet. We wait to learn who will answer EU questions in the Commons, since it can't be Frost. It does not look like an attractive job to me.

SNIP

.... responsibility for EU relations will in future be spread across three Whitehall departments in what looks like a recipe for confusion and endless turf wars.

It is difficult to believe that the appointment of this abrasive individual is intended to promote "Cooperation" within the TCA nor harmonious relations with our "friends" as Johnson insists on calling other nations.