Usually users search a specific unit conversion, such as “convert meters to feet”. They will be redirected by a search engine to a dedicated page with detailed units descriptions down below the category page, example https://www.betaconvert.com/length/meters/feet , do their conversion and leave. For the case when a user begins navigation from top-bottom, we will consider to load a proper unit description on unit change as you have suggested.
Usually users search a specific unit conversion, such as “convert meters to feet”. They will be redirected by a search engine to a dedicated page with detailed units descriptions down below the category page, example https://www.betaconvert.com/length/meters/feet , do their conversion and leave. For the case when a user begins navigation from top-bottom, we will consider to load a proper unit description on unit change as you have suggested.