Not sure there is any advantage of the MSD approach. More that I have several of the devices and would like to recycle them as they have a lot of use potential. They were bundled with a lot of motherboards as a display for various Windows Sideshow widgets and system monitoring.
I'll have a look at the STMicro package, thanks for the pointer. Though I'm seeing what seem to be uart headers on some of them, I'll prod them and see if this is more fruitful. As you say, keeping the host port free would be nice.