I’ve never dissected a dead person, but I’ve definitely dissected a lot of other animals. Dissections help us understand how organisms’ bodies work, and how they may be very similar from each other or very different!
I’ve actually done quite a lot of dissecting humans who have donated their bodies to science. I used to teach first year medical students in the Gross Anatomy lab, and also did a lot of dissections for plastination like “Body Worlds.”
Some of the detailed dissections that I’ve done have helped me gain a better appreciation of the relationship of the muscles to the bones that they move. and also the marks that they leave. This helps you visualize the soft tissue (and the living anatomy) when you only have the bones to work with.