There can be hardware-driven requirements that force you to simply have data in a particular place in memory, and if you want that data to hang around you might

There can be hardware-driven requirements that force you to simply have data in a particular place in memory, and if you want that data to hang around you might need to manually move it somewhere else. There's also the case where your API accepts a pointer and a size, but you don't want to have lingering pointers into the caller's memory, so you have to copy the data over to the "inside" of the API. This kind of design is perhaps less common in demo software, but certainly plausible in embedded products which at least try to be somewhat optimized.