All anti-spam rules and customer specific rules are generated and delivered via Broadcom servers, hence need the conduit to poll for them and download updated rulesets.
Gatekeeper/compliance rules are those policies and actions that YOU define locally on the control center, hence using a different process/channel for delivery to the scanners from the control center.
In the general case, unless you are specifically directed to by Customer Support, I would recommend against deleting rulesets. The system is optimized to download "deltas" from the Broadcom servers whenever possible. If you delete any of the AS rulesets (e.g. spamhunter, regexfilter, etc.), as long as the conduit is running it will self correct, but it will force the download of entire rulesets, rather than the deltas.
In the case of the Gatekeeper/compliance rules, the rulesets are, compared to the AS rules, very small and need no such optimization, so a "save" of a compliance rule will deliver the entire ruleset to each attached scanner.
Hope this helps you out.