I’m teaching (trying to) GTD to all my team, to enable us to share a common language and methodology for getting things done. Part of the work is to find the shortcomings of the workbook.
The book puts much emphasis on having a physical paper tray to manage paper stuff. The step feels useless in an almost paperless world, there is not enough paper in life, for it to be worth the space used by a tray on a desk.
Change all reference to paper with “physical stuff”.
Use the tray to hold the physical stuff that needs attention, like the toy of the kids that requires a battery change or that piece of jewellery that needs a repair, or even shoes needing new laces. Put that in your physical tray.
PS: You can use a box instead of a tray!