The boost to oneself is quite limited.
"I don't really like the feeling of riding a broomstick."
Tao Yu said as he took out the "Spellbook" and brought it along, preparing to take a look when the time comes.
This is a magic book borrowed from the Forbidden Book Area, which itself represents some dangerous magic, with Black Magic only occupying a rather small portion.
The reason that the "Spellbook" ended up in the Forbidden Book Area is that it records almost all spells, including a few quite powerful Black Magic spells.
Tao Yu relies on his 'knowledge' authority, making his efficiency in browsing such books optimal, gaining new insights with each reading...
…
"Aha, Tao Yu, you're quite the rare guest, make sure to guide us when the time comes."
Oliver Wood, upon seeing Tao Yu reading in the Quidditch Training Ground stands, happily ran over to greet him.
