That's precisely why I don't use them. I guess I do have a few, but none that I've used to merit their convenience. I find it's easier to just Google anew what I'm looking for than trying to navigate my phone's UI to find the few bookmarks I thought I might need. Example: there's a restaurant an Uber driver suggested to me and my gf over a year ago; I bookmarked it, and we both promptly forgot about it. It's still "bookmarked" in my phone, and I don't even know what kind of cuisine it is, but I was apparently arsed enough during our ride to save it.
Bookmarks to me are like coupons: yeah, I'll save them with the complete intention of using them, but they'll ultimately amount to clutter, expire and get tossed. (Yeah, I'm that asshole who walks into "Bed Bath and Beyond" and pays full price because I couldn't be bothered to remember the 25% off coupons they've been stuffing in every US mailbox for decades. The look of shock on both clerks' and fellow customers' when I announce I DON'T have the coupon is classic.) Meanwhile I can't find my passport or social security card, y'know, stuff that actually matters. (Idiocracy was less a comedy and more a prophecy.)