The chapter opens by naming two activities in one breath, governing people and serving heaven, and then says that one thing covers both. That pairing is worth stopping on, because it says something about the world the book was written into.
Serving heaven was not a metaphor. A ruler of the period held his position under a mandate and discharged obligations by sacrifice, calendar, ritual observance and the correct performance of seasonal duties. Governing people and serving heaven were two halves of a single office, and any adviser addressing a sovereign was addressing both.
What the chapter does is supply one virtue that answers to both, and it is a domestic one. Sparing use is what a household practises with grain and cloth, and the chapter proposes it as the whole of a ruler's religious and political duty at once.
That move is characteristic. The book repeatedly takes a value from the low end of the social scale and applies it at the top: the uncut block, the valley, the infant, the water that goes to the despised places, the rulers who call themselves orphaned. Here it is thrift, and the chapter treats it as sufficient for the two largest responsibilities a person could have.
The reception followed the political reading. Advice on husbanding a state's resources rather than expending them on display, campaigns and construction is what this chapter offers, and it was read that way in the centuries when the book circulated as counsel for rulers rather than as a devotional text.