What they want is have a specification which says that "EXPR if CONDITION" is 1) legal, and 2) states what it means. There are benefits to having a specification constructed by a specifications body. The benefits gets bigger if there are more players. Perl, being a relative small language, with just one vendor (that is, just one entity that produces Perl) the benefits are smaller than for instance C, with millions of coders, and dozens of compilers.

I don't know whether Perl would benefit from getting a standard. It depends on what your goals are, I suspect. If you want to get more people to program Perl, and have it being used in more companies, you want specification more than if you want to give more flexibility to the implementors.