Using the hardware based version could cause a lot of problems with unsupported devices.
(My use case is not so much in downloading a video, I just want to be able to my Amazon Prime videos on my Linux computer at a better resolution than 720p.)
I used results from this Github search page (especially pywidevine) a while back to make a Hulu downloader in Go which I eventually had to remove: https://github.com/chris124567/hulu
I wasn't really a part of this scene but there appears to be some sort of weird competition among people involved in writing this kind of software so occasionally device keys would leak when they tried to get at each other which was great for me because it meant I didn't have to extract keys from a phone or NVIDIA shield or anything annoying like that.
There are relatively easy ways to download L3 content, but they are not as common because higher resolutions are available on illegal streaming sites and torrents. These sites break hardware Widevine or use other attacks to get the material.
For professional content, there is simply not much demand to develop a user-friendly way to break L3 widevine, as the market is already served by reasonably convenient illegal streaming sites and torrents that allow for higher quality video.