The two channels answer different questions. Paid search is the only lever that can be switched on this quarter, tested in a fortnight and turned off when cash tightens — and it produces conversion data on commercial intent faster than any keyword tool. SEO costs more up front, ramps over months, and leaves an asset that keeps working.
Used together they compound. Run ads on the clusters you are considering to learn which intents actually convert before commissioning the content; use organic rankings to decide where paid budget is being wasted defending a position you already own. The teams that argue about which channel is better usually have neither dataset in the same report.