As far as software is concerned, until we have proper liability for defective software, ala Civil/Mechanical Engineering (where one signs their name to the design to certify safety and fit-for-purpose), we have little right to call ourselves (Software) Engineers, and hence no real reason for a professional accreditation/certification body.
I also just looked at the website, and all of the membership levels look like rankings in a guild system to me. Spend your time, pay more money, rise in ranks. Protectionism at its finest, and even though I'm heavily a software developer, I'm still against this burden.