Make hills, heat homes. https://en.wikipedia.org/wiki/Nanjido
In the 80s from what I understand, in response to the Mobro 4000 incident: https://slatestarcodex.com/2019/01/01/what-happened-to-90s-e...
That's not to say it's better than many alternatives (the article claims it's better than most landfills), but let's call it what it is.
Not quite. It turns out that even the ashes have their uses [1].
Of course oil-fired power plants aren't really used anymore (at grid scale), so it's more like recycling trash into coal or natural gas.