There's a difference between using the computer and expecting privacy on it. It's entirely possible that you're not supposed to use certain equipment for personal use, but if you do it anyway, that doesn't erode your right to privacy.

I'm not saying this is always the case in the EU, though. Obviously there is equipment where for many reasons it's absolutely vital that you don't use it for anything personal. I'm not supposed to run a torrent client on the company server, for example. You can't just "borrow" a company car for a personal trip. But when I happen to use the laptop that the company has assigned to me to work on, to do a bank payment, my boss has absolutely no business knowing the details of that transaction.