The whole voice back read back is a redundant part of the process, particularly with datalink equipped aircraft
That's not entirely true. There are two different types of PDC system: A one-way system, used in Australia and the US, where ATC sends a PDC to the aircraft by ACARS via the airline's host computer. ATC don't know the aircraft has received the correct clearance unless it is read back.
The other PDC system is a two-way system, used in Hong Kong, Bangkok, Dubai and parts of Europe, to name a few. The crew requests a departure clearance via ACARS. The ATC PDC system responds with a departure clearance message which is uplinked directly to the aircraft, again via ACARS. The crew then reviews the clearance and accepts it via ACARS, whereupon another message is downlinked to the ATC system. That message is checked by the system, a further 'Clearance Confirmed' message is uplinked to the aircraft and there is no requirement for a read back.