Many -runit packages do not, so runit writes to /etc/runit/sv/*/supervise.
This can place more burden on poor microSD cards.
I partially agree with this but i think another solution would fit better: instead of symlinking /etc/runit/runsvdir/default to /run/runit/service copy can be used. In that case supervision is done on tmpfs and there will be possibility to start service without enabling it
Is it possible to start services without supervision by default? Copying /etc/runit/runsvdir/default to /run/runit/service is also a good idea.
Runit is a supervisor by design. if you need to start something without supervision, do it at stage 1 or with rc.local