The Google translate isn't always accurate, no. It can convert words, but it does poorly at the grammar and language structure. In addition to an English translation, you're welcome to also post in Spanish or Portuguese. I read/write Spanish, and can fumble my way through Portuguese okay. So always post English, but you can add Spanish/Portuguese, too. It might help.
I think part of the translation was butchered, yes. But I'll guess my way through the question.
Yes, most cases are bad.
It's one of the sad truths of digital optical media. Most blank discs are mediocre quality, many DVD burners and DVD players are not very good. Consumers insist the products be cheaper than is realistic, so we get crap instead of quality products much of the time.
All wallets scratch discs. Sometimes the scratches are microscopic, too, not visible to the naked eye. Only use a wallet when the discs will not be pulled out a lot. I use wallets to store seldom used discs, like software discs. Some of my movies (used movies, came with no case) in wallets.
Cheap plastic cases can warp discs. So watch for that. Only uses cases that keep a disc naturally flat. Some plastic case spindles -- the little round part that holds your disc -- damage the inner ring of a disc. Watch for this. Only uses plastic cases that hold a disc, instead of putting lots of pressure on it.
I use spindles to store seldom used backups. The spindles are stored out of the light, in a file cabinet, a drawer or a dark closet shelf.
High-traffic discs -- discs I use a lot -- are kept in CD jewel cases or good DVD cases. My DVD-RW and DVD+RW discs are kept on small 10-disc spindles.
I hope that answers the question for you.