Aside from the obvious practicality to a need for more space and the additional performance that may surprise any unsuspecting really do struggle to appreciate the R estate.
Think my view is a little tainted as the reason selected the R Hatchback was because the Audi A3 Sportback looks too much like an estate! so this is maybe biased to taste but think the R estate looks awkward with the extension bolted on.
Think what also makes it look awkward is the 4 tailpipes which work for the hatchback but seem out of place on the estate, sort of contraction to its practicality than a leaning to its sportiness.
Aside from those who genuinely need the additional space personally you would think the R estate was more aimed at the company demographic? Someone who is on the road most of the time carrying their products, tools, displays around? Most company drivers who do high mileage would steer clear of the R estate simply based on economy, so you have excluded the majority right away with only the exceptions?
So be interesting to know the sales of the R estate both to public and to company drivers?
One last thing did surprise me is that only two of the exhausts function, the other two are purely for aesthetics, and think the knowledge of that would niggle me, and more support to just going for twin pipes which would for me make the estate look more joined and complete, rather than extended with the R back end bolted on. Think someone said in this thread, more stealth would make the R more.
Also, think it lacks the LED clusters?
So my not getting the R estate is based purely on aesthetics and for some economy, the one thing have no doubt on, is that once in the cabin and driving, the experience is every bit as good as an R can be, and sure its very satisfying in catching some unsuspecting out, who thinks its "just an estate"

Just personal preference from someone where the hatchback gives me all space need 99% of time and has an already aversion to estate styling.