To be fair, I have not tried a modern version. But the way that I use a modern terminal, I probably would not care for smooth scrolling.
Simply, I would not want anything hindering the dumping of information to my screen. I am no longer rate limited by baud rate, racing to hit ^S and ^Q to pause and continue the display output.
Rather, I'll hit a command, let it dump however many lines it wants, and then scrollback in the buffer with the scroll bar to see what I missed. This also effectively pauses fast moving output as the buffer continues to fill while I'm scrolled back.
If the information is still flowing so fast I can't make sense of it in my text window, I can either search on the text live, or Select-All, Copy a large swatch of it, switch to another window and paste it into an editor buffer and have my way with it.
My terminal buffer has "infinite" scrollback. Yes, there have been times when I've left processes running over the weekend to come back and having my machine cratered with swap because my terminal buffer was far, far too large, gorged with logging messages. C'est la vie, I'll take that minor inconvenience over the flexibility of an infinite scroll buffer.
The modern terminal environment for me is quite different from the old VT-100 days. Perhaps if the smooth scrolling was faster I would not have minded it as much back then, but it wasn't and I found the default VT-100 rate too slow. Data can scroll by too fast, but there was always other mechanics to pause and such that I can use as much or as little as I wanted, rate limited by me rather than limited by the terminal. I found that way much more flexible and suited to how I consumed information.