Venus keeps getting dragged into compatibility quizzes because Venus rules the 7th house in the natural zodiac. That single fact does a lot of damage. The 7th house is the partnership axis — cooperation, marriage, negotiation, the deal you strike with another person. Venus is its classical ruler, so yes, Venus belongs in the conversation. Relevant is not identical, and the shortcut from a planet to a whole relationship is where the quizzes live.
So does Venus matter for compatibility? Yes, as one input. A compatibility reading worth trusting compares two full charts, not two Venus signs. Start with the synastry chart calculator, which needs both people's birth date, time and location — with one chart only, you get a description of one person's taste, which is a different question. Two-chart comparison is a developed craft, and a worked pairing such as Libra man and Scorpio woman shows how many layers sit between two signs and two lives.
Is the love-language framing ever useful? It is useful as a conversation prompt and useless as a chart reading. Love languages describe how someone prefers to receive care. Venus describes what they find beautiful, pleasurable and worth having. Those overlap at the edges and diverge the moment money, loyalty or effort enters the room.
Why does my Venus sign describe me badly, then? Often because you are reading the Sun-sign version of it — the generic, sunniest take written to apply to millions. Your actual Venus sits in a specific house, makes specific aspects and answers to a 7th-house ruler and a Moon that the generic description never mentions. The generic version flatters. Yours does not have to.
What if the placement describes my ex better than it describes me? Then check whether you are reading a description of what you pursue rather than what you protect. Attraction style points outward at other people. Values point inward at yourself. A lot of readers recognise their Venus most clearly in the people they keep choosing — which is a clue about the want, not proof about the match.