I was quite surprised by that, then when I thought about it, not so much. Indeed it is a good idea when you see something to DEVONthink 3 it. There are other reasons, quite a few that an article can become lost unless you have your own copy. I always had the instinct to keep a copy in DEVONthink 3. I do have a lot of bookmarks these days though… nothing I couldn’t live without is the rule for that though.
I have to say that now that papers take up so little space you can save thousands just in case. I don’t actually but I have important ones saved. On the other hand I suspect those are the least likely to vanish?
Some tricky issues with paywalls and things I won’t pound sand on here. In general I tend towards open access and more are becoming that way, especially if the subject is not commercially important directly as it were. As MsLogica says an URL is not a citation though it is useful to include one.