Since I posted my last message, I researched the OneDrive situation a little bit more. It first appeared in Windows 8 in 2015. But Windows 8 was very unsuccessful and I personally never installed it, holding out for something better. I only moved to Windows 10 about a year ago, and for whatever reason I only noticed that OneDrive wasn't keeping files locally until three or four months ago. I've been phasing it out ever since. Of course, OneDrive is a part of a larger Microsoft strategy that I totally disagree with. Namely, put all your data in OneDrive and put OneDrive clients on all your devices. OneDrive of course is built in to Windows itself. Thus all your data is in OneDrive and isn't really on any of your devices. It's AVAILABLE to all your devices but it's not really ON any of your devices.
I think OneDrive was around before Win 8 / 2015 in the guise of SkyDrive but I seem to remember MS renamed it (perhaps because of clash with Sky?) and in the beginning you didn't need to install anything (and I think that's still the case?) you just log in from your browser and use if that's what you prefer.
Like others mentioned it works as I expect it to, I use it to keep some files available anywhere, collaborate with others and on odd occasions when I have been away from home backup files from my laptop. Its never been part of my home backup strategy.
One current negative, when first launched it came with 25GB of free storage but has been cut back to just 5 last time I looked :-(
I'm not keen on a lot of what MS has been doing but happy with OneDrive :-)