It is the highest-ceiling link tactic and the highest-variance one. A campaign that lands produces dozens of editorial links from sites no outreach budget could buy; a campaign that misses produces an expensive asset and silence. The costs are front-loaded in the asset, not in placement fees, which makes the cost per link excellent on success and terrible on failure.
What separates the two is usually the angle, not the production quality. Journalists cover surprise, conflict, scale and local relevance; they do not cover a brand's opinion of itself. Data you own — from your product, your customers, your industry — is the most reliable raw material because nobody else can publish it first.