I can't answer for the OP, but since this is an old thread and I'm not sure the OP will be by to answer, I'll give you my thoughts
I think he was saying that while those things create aerobic areas they do not provide anaerobic areas. And while they will convert ammonia to nitrite to nitrate they wont help convert nitrate at all. If used as an aerobic area they will build nitrates and become what is referred to as a nitrate factory. When use as a filter as you described they are fine, as long as frequently cleaned completely.
Thanks for the response. This helps answer why it is good to use a mechanical filtration so long as it is cleaned regularly. It also explains why using bio-media is bad since they are typically left in the system and collect detritus.
I agree with you . No abbreviations would be helpful until us newbies learn the lingo. And some simplification would also help. But on the other hand , I do appreciate the time spent , and it did help. Thank you