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.
Liability doesn't make sense for a lot of software. It's not like electricity where it's always potentially dangerous, civil where mistakes can cause death and dismemberment en masse and so on.
Basically software liability is just rolled up into the relevant market. Writing facebook games? It doesn't really matter to society if you get it a bit wrong. Writing pacemaker software? Then you're governed by medical device regulations.
Software's application to problems are so varied, so wide, that it's insensible to apply a single liability scheme to it.