Search captures demand; social has to create or qualify it.
For Australian buyers, paid search is the channel that intercepts an intention that already exists, which makes it the natural first channel and the one judged most directly on cost per qualified enquiry. Meta works where the category is visual, the purchase is consumer or considered, and demand needs to be created rather than caught. LinkedIn earns its place when the buying decision involves a defined job title and the deal size can absorb a materially higher cost per lead. Each gets a stated job before it gets a budget.