Short answer: because AwardFares (and similar award-booking services/tools) find and book award space airlines’ own sites often don’t show or handle easily — saving time, unlocking partner/complex routings, and using expert ticketing know-how that most consumer sites and apps lack.

Key reasons travelers use AwardFares

• Better visibility of partner inventory: Many airline websites don’t reliably display all seats released to partner programs. Award-search services aggregate partner availability across carriers and programs so you can see options an airline site might hide.
• Cross‑airline / mixed‑alliance itineraries: Services can build and ticket itineraries that mix multiple airlines or alliances (open‑jaw, multi‑city, stopovers) which can be difficult or impossible to assemble on a single carrier’s website.
• Complex routing and mixed cabins: They can search for and price mixed‑cabin trips, long connecting routings, or unusual routings that yield lower award prices or rare premium cabins.
• Expertise with award rules & routing tricks: Agents know program quirks, routing rules, fuel‑surcharge workarounds, and when to book by phone vs. online — often turning up cheaper or otherwise unavailable awards.
• Phone‑only or agent‑only space: Some award seats are released only to travel agents or require phone ticketing; services can access and ticket those.
• Time savings and convenience: Rather than spending hours hunting availability across dozens of sites, users pay a fee for a service that does the searching, constructs the itinerary, and issues the ticket.
• Reissues, holds, changes and support: AwardFares-style services typically assist with holds, ticketing, cancellations, reissues and disputes — helpful when airlines’ customer service is slow or confusing.
• Calendar tools and alerts: Many services offer more powerful calendar views, multi‑airport searches, and alerts that make spotting saver availability faster.

When to stick with airline websites

• Simple, single‑carrier trips where you’re redeeming only that airline’s miles (no partner segments).
• If you want to avoid third‑party fees — airline sites are free to search/book.
• If you prefer to manage changes and cancellations directly with the loyalty program.

Tradeoffs

• Cost: award services charge fees (but many users find the time saved and value found outweighs the fee).
• Dependence on agent accuracy: make sure the service has good reviews and clear refund/void policies.

Bottom line: use an airline website for straightforward award bookings; use AwardFares-style services when you need broader inventory, complex routings, phone‑only ticketing, or expert help to squeeze more value from your miles.