That Quad I/O mode lets you read four bits per clock cycle, which roughly quadruples the throughput over a standard SPI read — useful when you are shadowing code to RAM or logging data at speed. The part runs on a 2.7 V to 3.6 V supply and is rated for the industrial temperature range of -40°C to 85°C, so it fits outdoor telecom cabinets, factory-floor controllers, and any enclosure that sees seasonal swings.
Quad I/O at 108 MHz reads four bits per clock cycle.
One source marks this part as end-of-life hot; another lists it as active. Treat this as limited factory support.