For archiving important docs, I buy 64GB flash drives and put them in baggies in a safe to keep the moisture out. And because they are relatively inexpensive, one can do this multiple times so if there is one failure, you have another copy.
You do understand that when you program flash, you're essentially charging a capacitor, right? And that, like all capacitors, the charge in flash leaks off?
Last time I looked into it, flash was only rated to hold its charge for about 10 years.
In 10 years, you would probably have a difficult time finding a device that's physically compatible with anything we are using to store data on today.(if history is any indicator) Of course, USB and CD type drives have stuck with us for a long time now, so I could be wrong. You'd probably be challenged to now find a new machine with IDE connections.