Your friend sounds like an outlier in these circumstances; the certification is more likely to be of benefit to those fresh to the field, and in the field of child-care (and aged care also), I think some bare minimum requirement of capability is warranted.

Professional training organisations may not have direct experience with the subject matter, but given a good curriculum prepared by someone who DOES have experience, I don't see why they couldn't deliver a reasonable result. I agree that any "Q and A" sessions, or questions along the lines of "What is it really like working as a..." would not be that useful, though.