Hello
interesting topic, i have no clue with tinuG itself but I played alot with Raspberry-alamode-cncshield, which is sums up-to to one package computer, controller and break-outboard.
1. Running Grbl Controller on Raspberry Pi | zapmaker
What I experiences was that it worked very well for running basic programs and cnc movements.
Though I experienced a lot of issues with IO voltage level of 3.3volts. Bigger the machine, longer the wires. And induction becomes issue, as signal setup was active high.
3.3V system starts to consider about 1 volts to be On signal and its easily peaked from EMI and induction.
So if you plan to use IO, meaning limits, tool height etc. there is chance it becomes interesting.
If you don't care about those, you wont see any difference between small and big machine. Juts use outside drivers for steppers and you are fine.
Or does tinyg provide active low? or did you manage to solve this issue somehow cleverly. Perhaps signal level shift or something...