Crowdsourcing a penetration test through Bugcrowd's Flex model offers four main benefits: 1) You pay only for valid vulnerabilities found rather than researcher time spent; 2) Engaging many skilled researchers across different specialties increases the likelihood of finding issues; 3) The reward structure encourages in-depth testing by incentivizing top submissions; 4) This results in significantly more testing effort within similar timeframes as a traditional penetration test.