A positive step
My personal feeling is that if the media is rated for that long, there will be some effort made to make sure that, at least in the medium term, that the media can be read.
Couple this with the fact that it is piggy-backing on a consumer level technology, and should be able to be read on any BD-XL drive means that there is a higher chance that devices will continue to be made into the near future (decades) that will read it. I know that it is not really a good comparison, but CDs are still readable in current generation BluRay readers, so that shows that a medium with sufficient market penetration can still be readable nearly four decades later.
I know that this is not anything like the 1000 years specified for this media, but it is suitable for medium term (decades) archive of financial data in a way that current generations of disk/tape technology is not.
I'm not going to suggest that we should stop using durable physical media for the intelectual riches of our society, however, because when the technology fall happens, anything that is not readable by eye will be useless anyway!