A little off OP’s topic, but the conflict of interest rules extend into client services. The Big 4 audit engagement partner has to rotate off the audit engagement every cycle (4 to 5 years?). Also, a Big 4 firm cannot provide full services (consulting, tax, advisory, etc.) to its audit clients.
Regarding OP’s posting, having Big 4 firm experience on a resume is almost as good as having a top 25 to 30 MBA school on the resume. The exception is T7 to T12 schools.