I know from experience some of these apps use mac address to enforce the free trial period (e.g., download 3 things for free then be forced to pay). If you have a means to install it in a vm and change the mac...
They download the file (which you can usually do with a little Inspect Element action + yt-dlp), but then also decrypt the file.
Most of the big streaming services use Widevine DRM (or at least did at one point, I might be outdated by now), so just downloading the file gives you appropriately-sized gibberish. These apps tend to be expensive because getting around the DRM is usually non-trivial.