CD/DVD wallets have a huge defetc: they can warp discs. Moreover, the plastic sleeves can also scratch discs when you insert/remove discs from them.
A warped disc is unreadable, and it actually can also damage the drive if you try to read it.
The best way to store discs is the jewel case. Yes, I know, it is the most cumbersome solution, but it is also the safest one.
A reasonable alternative are cakeboxes (most blank DVDs are sold in these boxes, so it is a safe way to store discs), but they are also uncomfortable when you need to search for a specific disc.
Did you notice that very often when you search for a disc almost always the disc you are searching for is the last one in the pile?