This is not for mining, this is for holding wallets only, hence the encryption. I plan to avoid even connecting this online too much.
i would also suggest you backup your wallet.dat files onto cd AND dvd. perhaps multiple copies of each. WHY cds AND dvds? only due to the idea that it may be difficult to find a CD-Rom in 10 years. dvd is likely to fully replace it by then.
either way, you will WANT multiple, physical, copies of each wallet you associate a value to. fire, data corruption, etc. can occur.
i may be paranoid, but i wear a flash drive around my neck with an encrypted copy of my "savings" wallet. this is just one copy, mind you:)