HA Enable On/Off UI Differences

What is the effect of only enabling HA on the /ui/ha/settings page - What is the difference between these two settings? Are they independent of one another? Is HA effectively disabled if BOTH are not in an enabled state?

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But on the /ui/ha/deployment/summary you leave it unchecked - does this mean that HA is enabled for the polling engines out bound polling, but the VHN/VIP is NOT enabled for incoming data?

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