That only works when you're copying to the same OS. You run the change of entering into a world of hurt if your new device runs on a different platform.
Do you not use bookmarks? Or are yours so stable it isn't any work to keep up?
This makes tons of sense to me with extensions and the other profile data, but not that.
I just let them diverge. Most bookmarks I make are needed for a span of less than a week or I never use them again in the end. It's admittedly kind of a chaotic solution, but it works for how I use the browser.