The key thing here is that this interface is a digital interface; you don't need the ultimate in cable quality to get the ultimate in displayed quality. A bit of wet string could almost do the task (assuming it had 19 strands and the correct plugs on the end... ;)
So this wonderfully long cable allows digital input to get up to the wall-mounted screen, and keep all the quality of HD. But without the boxes (HD source, Xbox, PS3, etc) being on display. Even makes up-scaled DVDs look good!