Nice job. I'm a noob to "dice tray" did a Google and most were just flat, or scooped trays to evidently hold dice. Yours could also do that, both in the box, and on the tray, but the tray fronting the box as it does, and with the catch rail all around the field, is this maybe more appropriately know as "craps in a mobile environment"
Whatever the end purpose, it looks well made, and is certainly functional for any and all mentioned here.
Thanks for sharing, Google images didn't have a pic of one anything like yours, Etsy is calling your name, at least for a week or 3.