Frontpage was my toy as a kid! Others would play with Paint or Solitaire, I was all about making fake websites and projects over and over. I agree it is very intuitive and while now I very much prefer coding by hand, I do remember the drag and drop, very "Microsoft Word" styled page making taught me a lot about HTML. Even then, there's def an option in Frontpage to just write code and see it in live preview, so what's not to love xP As far as I remember (wait nah, read this as "as far as I could do at the time"!) it only supported inline CSS, but that might also be restricted to the older versions: refusing to believe something from the mid 2000s wouldn't be able to support or write external CSS files!
The most popular way to build simple HTML pages now is undoubtly's Neocities online tools, but I'd love to see a "What you see is what you get" version pop up too, just like Frontpage.