I have a wallet on blockchain.info and another on my machine using bitcoinQT. For both I have the latest print out. Now if...
1. Somehow I cant log into blockchain.info, then will I be able to use my coins using my paper wallet ?
2. Somehow the data file of my bitcoinQT gets corrupt, then will I be able to use my coins using my paper wallet ?
yes paper wallets will give you access to you coins. But for bitcoin-QT you had better backed-up your wallet.dat file, as there are a number of private keys in it, not only one.
Also, if you have any considerable amount of your holdings in crypto, buy yourself a hardware wallet and secure your coins once and for all.
The hardware wallet is secure even if stolen or lost because it is PIN protected and you can recreate your wallet on a new
device from your 24-word recovery seed. That 24 words is something that must be protected and never disclosed to others.
Then, after all your funds have been secured, it is OK to keep a fraction of it online (on blockchain.info or others).
At least, it is what I would do.