LMH6525: may I ask, how is the Read Channel applied and what are its main use cases? Thank you

This device is designed for CD/DVD writers. The datasheet says:

Channel Enable Inputs

Each of the four channels has one (read) or two enable inputs that allow the channel to be turned on or off. The read channel enable (ENR) is a single-ended TTL/CMOS compatible input. A single-ended signal is adequate for this channel because the read channel is generally enabled the entire time the drive is reading or writing. The three write/erase channels need to be operated much faster so these channel enables are LVDS inputs.