Cold throw is how a scented wax product smells before it is heated. Hot throw is the fragrance you experience once the wax is warm enough to release more aromatic material into the air.
A wax melt can smell powerful in the package but perform differently in a warmer, and the reverse can happen too. That is because heating changes how volatile fragrance materials move into the air. When evaluating wax melts, hot throw is usually the more useful measure of how the product will actually fragrance a room. Cold throw is still helpful when choosing a scent before warming it.
Think of cold throw as a preview, not a performance test. Smelling a cube close to your nose is different from noticing it across a room. A strong package scent cannot tell you exactly how the warmed product will behave in your space.
For a fair hot-throw comparison, use similar portions in the same warmer and room on separate occasions. Give each one time to warm, then assess it from your normal seating area rather than leaning over the dish. That is the experience you are actually buying the product to create.