This is most annoying. I have used this for the past twenty years and have not lost form data using it. In any event, chrome seems to remember form contents upon navigating back to a form page. Leave my muscle memory alone please.
I lose form data by accidentally using backspace like once a month. Glad to see it go. It's the worst kind of UI modality because it does different things depending on whether you've reached the beginning of the form. I like to mash backspace to clear out a form. Imagine if pressing "CTRL-S" saved if there were edits, but deleted your file if you'd already saved. People who mash "CTRL-S" habitually would be screwed.…
I've never seen backspace act differently once I'd deleted everything. If a form field has focus -- even an empty form field -- backspace doesn't make me lose the page.
(On the other hand, I started this morning hating Chrome for getting rid of the functionality I've used since last century, but I'm now coming to accept it.)