That's cool! I wanted to get an M5Stack anyway to play around with. A question about the secure chip: does the firmware actually recognize it is running on a M5 with secure chip & use it or is it not used? I mean, if it's not implemented, then having it on the PCB won't help.. 
M5Stacks are a great little devices and sometimes you can find them on discount deals for very cheap.Secure element is used for sure and it should be recognized, if you watch the video on their product page you will see that it is used for encryption.
Quote from:
the mnemonic is stored in an accessible location on the device
...
the wallet details are only pseudo-secure on the device
...
the wallet details are only pseudo-secure on the device
Maybe it's old info from before they supported this secure element, or maybe there's another reason that somehow makes the seed accessible, even though it's secured on a secure chip. A clarification would be helpful.