s6 is smaller than superd, reducing the size of the minimum install - I'd say that is the biggest pro otherwise, well, you have shell scripts (actually literally anything executable called run, it could be a symlink) instead of configs and avoid go
gopher asks: why would one replace an existing working approach to avoid go?
mafe: to avoid the go toolchain, which is extremely bloated, even including a package manager
tinygo seems to improve on this