A surprising number of people have tried the same workaround: spritzing their own cologne inside the car to make it smell better. It makes sense as an instinct. If cologne smells good on you, why wouldn't it smell good in your car? The answer comes down to how fragrance is actually built, and what it is built to interact with.
Cologne is formulated to react with skin, specifically with body heat and natural oils, which is part of what makes a fragrance develop and change over the course of a day. Spray that same formula onto fabric, leather, or plastic, and it behaves differently, often fading faster and smelling flatter than it does on skin, since it is missing the exact chemistry it was designed around.
There is also a practical issue: cologne sprayed directly onto car surfaces can stain or discolor certain fabrics and leathers, especially lighter interiors, since it was never tested or formulated with those materials in mind. A fragrance made specifically for a car is built to interact safely with the materials actually inside one.
And then there is the cost math, which nobody thinks about until it is pointed out. A bottle of decent cologne runs anywhere from $60 to $150 or more. Using it to scent a car, on top of wearing it yourself, means burning through an expensive product twice as fast for a job it was never designed to do particularly well.
A hanging car perfume solves the actual problem cologne was being asked to solve: a fragrance, cosmetic-grade, genuinely well-made, but engineered specifically for a car's environment, safe on interior materials, built for slow release over 2 to 4 weeks instead of one spritz that fades within the hour.
The instinct to use cologne was never wrong. It was just aimed at the wrong product. The car needed its own fragrance, not a smaller job for yours.