Linked from
The 21 pages that link to Perfect competition, each with the reason it gives.
MonopolyCompared with: It is the benchmark opposite to monopoly in standard models of market power.
Labor marketCompared with: It is the benchmark behind the competitive labor-market model.
Market powerCompared with: Firms in this benchmark accept the market price rather than influence it.
Search theoryCompared with: Its frictionless assumptions differ from costly, incomplete search.