You're right. Tinybox's 1.36 petaflops is FP16 so that is a significant difference.
Also, the Tinybox's memory bandwidth is 8064 GB/s, while the Digits seems to be around 512 GB/s, according to speculation on Reddit.
Moreover, Nvidia's announced their RTX 5090s priced at $2k, which could put downward pressure on the price of Tinybox's 4090s. So the Tinybox green or pro models might get cheaper, or they might come out with a 5090-based model.
If you're the kind of person that's ready to spend $40k on a beastly ML workstation, there's still some upside to Tinybox.
2 PFLOPS at FP4.
256 GB RAM, not VRAM. I think they haven't specified the memory bandwidth.