Port of Espruino to Pi Zero - native - no Linux

Hi, just a few arguments to this discussion:
a- the global bill amounts to 25 - 30 euros! (box+sd+power supply+wifi dongle)
b- running a rpi for month or years imply a bit of hardening on the linux side or you'll get sd wear: i have done than since 2 years now and finally openssl bugs imply reboots every 2 or 3 months
c- power consumption is definitly not iot friendly: stm32L4 seems very interesting from this side (nA somewhere)
d- no adc or dac on pi0
e- single uart
f- android tablets are getting as low as 30 euros