NotebookLM is extremely badly engineered: The large downloads don't work in mobile browsers. For the longest time, the downloads were in wav format which doesn't make any sense. The mobile app lacks much of the functionality too. The generated audio is often about an altogether different topic than the one I requested. And don't get me started about the quality of the speech -- it still has an occasional "third voice" problem that just doesn't fit in. Overall, I would say its UI fits the culture of shipping utter crap, and I would never hire any designer of that team.