You’re definitely not the only hot water bottle fan here. You’re in good company!
You’re right in that an electric blanket goes underneath the bedsheets but a heated blanket is literally like a blanket that you drape over yourself almost like a shawl. So, you’re effectively wearing it and it’s heated up so you can stay in your own cocoon of warmth without having to whack the heating on too high or even often. They’re very economical to run costing between 3 and 4p an hour.
I’m somebody who feels the cold far too easily so this is a must buy for me for Winter. The lovely @anon6309382 has got me fully converted!