As an addition, I've been trying their qemu image, and similar to an older, similarly radical distro "rsld" (the old release which was graphical), it's usable in qemu, with kvm disabled, to get a snappy graphical environment that can even browse the web (with all the limitation those simple webbrowser have). Browsing HN (using netsurf), while checking memory usage in a st window uses 56MBs of memory. IIRC rsld, which used dillo on tinyxserver, used ~25MB on something like wikipedia.

Other notable "radical" linux systems are EasyOS, RancherOS, Bedrock linux, Gobolinux, NixOS and Guix.