It also gives some people a sense of safety (by the illusion of being able to make sense of events).
Yes - something which many people are desperate for. And astrology, generally, is far less harmful than most of the alternatives.
Not sure about that. If people are convinced they are not getting along with another person because they are "lion" and then never do a real analysis of their communication failures, then I see a lot of harm for all the people around them, usually children.
If someone, even the ones who believe in astrology, believe it works that way, that's a problem with the person, not with astrology. Astrology doesn't state that x and y alone don't go well together. It points the struggles and harmonies between two sets of highly complex birth charts. Disclaimer: I don't believe in astrology, but I know a little about its ground rules.