Completely useless, but it seems I am not the only one.
Waited in for a delivery and got a message saying they couldn't deliver as I wasn't in. No delivery card and no photo. Difficult to find any support but got through to a support chat and they confirmed that the driver hadn't even attempted a delivery. But they couldn't do anything about it. Finally told they could not give out any sort of links for a complaint.
Would give 0 stars if the system allowed it and will never touch DPD again.