Bonhoeffer uses a similar phrase 'worldly Christianity'. It's J Gresham Machen that I want to line up most closely with. See his Christianity and culturehere. Having done commentaries on Proverbs (Heavenly Wisdom) and Song of Songs (Heavenly Love), a matching title for Ecclesiastes would be Heavenly Worldliness. For my stance on worldliness, see 3 posts here.
As we passed through a rain soaked Wales today I remarked to my wife that this was wild Wales. I suggested I should write a book on the subject so people could borrow it.
She was straight back with "By George, you should!". She's very quick.