The Ultimate Riding Jacket?

Looks to be more for fastpacking / spine racer types?

Not sure what advantages it'll give for off the bike end of day use over less complex jackets?

I would recommend a basic down vest or long sleeve that you can park under a shell - you want as many multi use items as possible for weight and space saving.

Gimmicky

Based on

more for off the bike at the end of a day's riding

and

not designed to keep you warm when stationary

it sounds like you'll be cold and sad (speaking as someone who has bought many stupid jackets and been cold and sad as a result).