You can call it “innocuous” all you want, it’s still an unnecessarily unsanitary thing to do. Just because there’s worse examples of gross people doesn’t mean getting your saliva on produce in the store isn’t also gross.
I personally like to keep them separate as I use the different devices for different purposes. I don’t really ever have more than the visible row of bookmarks at any one time. If I need to save something I’m not using often, I’ll archive the page. Like for recipes in particular I have a directory filled with them.