I am one of the 200 tab people but it's not all in one browser window. I use a Firefox extension called 'Simple Tab Groups' that let me categorize the tabs to get back to them later. I use it as a mini-knowledge base (I'm not that attached to my tabs if I lose them, I use Yojimbo for my real KB).
But just to say it: I also freak out when I see someone with so many tabs open that it's like a little Joy Division cover on the top of their browser.
They are easier to create and remove. They advertise their presence, reminding you to come back and read them better. They can load faster since. They save your scroll position. They save the state of the site and input fields.
The other use case for bookmarks is creating a new tab and navigating to some website like a blank google doc, twitter, hacker news, etc. This is better handled by history. The most frequently used sites can show up on the new tab screen and show up in the results when you start typing in the URL bar.
I don't see any advantage to regular bookmarks for 99% of use cases. They seem to be a feature that exists due to limitations of hardware and browsers from the early days of the web. It's similar to YouTube. In the old days you had to subscribe to channels. Now YouTube is advanced enough to not require you to subscribe to anyone for it to give you content that you want.
But just to say it: I also freak out when I see someone with so many tabs open that it's like a little Joy Division cover on the top of their browser.