The ink has extremely limited capabilities. Let’s say you make all the proposed enhancements (glossing over the numerous problems that would be caused by mounting ink tanks to the hotend assebmly). Even if you’re content with only buying white or translucent filament, you still won’t get the vibrant colors you get when liquid plastic is dyed. Additionally there’s the concerns of what this ink might do to your hotend, is it safe for the ink to be at 240+ degrees, will the ink affect bed and layer adhesion, and what will cause the ink to run? There are just too many things wrong with the fundementals behind this to warrant much further development when there are much more effective options already on the market.