Different set of tradeoffs that not all grok, in part likely because bitcoiners are perpetually bombarded with a marketing narrative declaring HWWs as the most secure way to interact with private keys. Different tools are appropriate for different people and different use cases, but SeedSigner is entirely a viable option "in practice".
Discussion
I love how people think the rasperry pi is closed sourced but the STM32 is not lol. 🤣 Show me the github for the stm32 rom and I'll change my mind.
Can't speak for all projects using STM32.
But every single OP code on COLDCARD is open to review and reproducible. RDP=2 changes the memory map to put our reset vector as first bytes executed. Full part number: STM32L4S5VIT6 check the COLDCARD code and docs to verify it yourself.
It was quite the feat to make it work like that in conjunction with the 2 other secure elements!