Split on standalone search demand and distinct intent: a question earns its own page when it carries its own demand and your page can be the best answer to it, and it belongs as a section when it is a sub-point of a broader intent that is better served alongside its neighbors. The pivot is standalone-demand-and-intent, not a blanket rule in either direction. Neither “every question gets a page” nor “fold everything into pillars” is right, because both ignore what the searcher is actually doing.
A question carries standalone demand when people search for it directly, on its own terms, expecting a focused answer rather than a chapter inside a larger guide. When that is true and you can genuinely be the best result for it, a dedicated page concentrates relevance on exactly that intent and competes cleanly. Spreading that question across a section of a broader page dilutes its focus and forces it to compete from inside a piece optimized for a different primary intent, which usually loses to a page built for the question itself.
A question belongs as a section when it is one step in a larger journey the reader is already on, with no meaningful demand of its own. If almost nobody searches the question in isolation, and answering it only makes sense in the context of the broader topic, a standalone page just creates a thin, demand-starved URL that competes with your own pillar and reads as filler. Folded into the bigger page, the same answer adds depth where the reader already is, which is where it does its job.
This is the plan’s own question-equals-page gate in miniature, and the practical move is to run that gate before you split anything. Check whether the question has standalone search demand and a distinct intent you can win. If it does, give it its own page; if it does not, write it as a section of the page that owns the broader intent. Decide on demand and intent, not on a reflex to fragment or to consolidate.