The heatsinks aren't that cheap, there like $30-40, and four of them would be $120-160. They're rated at 320W cooling power.
"Professional" does not mean high-grade/pointlessly expensive stuff, a lot of the time it means it gets the job done without much concern for aesthetics. It should last a long time and be reliable, but that doesn't mean it will look nice.
A $30 cooler is not over-delivering, which seems to be the knc mantra.
What is some guy announces on the fourm "Hey, I've figured out some way to make a jupiter hash at 600! More heat - you'll need to upgrade those arctic heatsinks though". Then 1000's of miners tampered with their box and no longer have a warranty

No but providing a cooling solution in excess of the products needs is. They already stated at the openday their cooling option is overkill. Arctic are a solid brand. This isn't about pissing monies up the wall, they are not profiteering. It's about reclaiming NRE, whilst remaining competitive.
Thinking out loud, if their power requirements are advantageous, one heavy duty external PSU may power more than one device, saving cash.
Certainly we know customs would be an issue with internal PSUs, which is why BFL went that route, and Bitsyncom had to. ASICminer never had to concern themselves with this. Aside from anything else, larger casing = large dimensions & greater weight = more expensive shipping fees.