Kafka leans heavily on the OS pagecache for data storage ?

["Malik, Shibha (GE Renewable Energy, consultant)" <Sh...@ge.com>]

"Finally Kafka leans heavily on the OS pagecache for data storage. Although the question says that kafka writes to disk immediately, that is not completely true. Actually Kafka just writes to the filesystem immediately, which is really just writing to the kernel's memory pool which is asynchronously flushed to disk"

Is this true and that is the main reason eventhough kafka uses disk to store data is still faster than a lot of in-memory message queues ?