As a PhD candidate (post classes) I honestly use those lectures a lot. No, I do not find a massive classroom better than an online lecture. Actually worse. The advantage of a classroom over a video lecture is the ability to interrupt and ask questions. To have the expert in front of you. In this day and age, sitting in a classroom and not participating is an entire waste of money and you're doing yourself a disservice by not participating.

I actively remind my students this when I teach, who honestly are less active post pandemic. It is something I worry about. And though my account is "anonymous", if you ever show up to my lectures, not as a student but just sitting in (I don't take attendance, idk if you walk off the street and want to sit in), you too are welcome to participate.

(Fwiw, there aren't really "PhD level lectures" so much as graduate lectures. Generally you stop taking classes at the end of year 2 in your PhD, which is equivalent to a masters. The distinction of the PhD is that you are learning to learn on your own. This does add extra context to why grad students ask for higher pay, especially at the non-conditional and candidate levels, as they're actually taking less resources from the school. E.g. I pay the school $10k/term (big round) for research credits, which requires no involvement from anyone. There no longer is the "student" part to my "51% student, 49% employee" split)