While you can update homeassistant with a single command, you can not check updates for updates on all add-ons also but instead, have first to iterate over the add-on list and then run a check on each slug:
for addon in $(ha addons | awk -F ":" '/slug/ { print $2 }'); do
ha addons update $addon
done
This should be changed into using a wildcard character. Also, if no update is found, its says “error” but that’s the wrong context, since when no updates are found, everything is fine. The return code also shouldn’t be 1 in that case.