Odd. To me, something labelled "archival" means "is expected to last a really long time, and be especially robust."
I _think_ that's what it means to most people. Although it's hard to say. But compare to wikipedia says "Archival paper is an especially permanent, durable acid-free paper." Especially durable and permanent, not especially fragile and needs to be treated with unusual care!
If they are marketting something as "archival", I am reasonably certain that _many_ people are going to think that means "especially durable and permanent", not "especially fragile, must be treated with care."
But yes, there are many more factors to long-term preservation of digital content than simply media reliability, including inter-operability with future hardward/software. Integrity of the bits on your media is certainly one factor though. And yes, multiple copies and regular integrity checks is crucial, not just counting on your media to last. Media long-term reliability still matters though.
(I work in libraries, and I work with and next to people concerned with digital preservation, although I don't work on long-term digital preservation myself).
No. I just suppose that packing that much information so tightly, encoded in such small features on a plastic disc, will make the recording more fragile. It's like printing all your text with a 3-point font. You can print a lot of text on a single page, but any damage to the page may make large parts unreadable.
As for long term preservation, I'd never suggest keeping your data on the same medium for any significantly long time. And never, ever, under no circumstances, find yourself with a single copy of anything.
In this context, long term durability has more to do with chemical attack from the atmosphere than being handled by human hands.
Having media that lasts for 100 years is little comfort either. What good would do floppies that last for 100 years when the only computer capable of using them here in my house is an Amiga 600?