Some tend to believe that the greater the amount of bio-media, the greater the amount of beneficial bacteria.
I tend to believe that the amount of beneficial bacteria colony(ies) rises and falls based on the availability of 'food' and oxygen. So on the food side, this is ammonia for nitrosomonas and nitrite for nitrospira. With this in mind, you could potentially have 'acres' of unpopulated (bio-media) real estate.
Given that there is a substrate, a sponge filter, and a fair amount of other bio-media as shown in the photo, I doubt that the PP water filter, while it could add benefit in water clarification due to it's micron size, most likely adds little or nothing to the beneficial biology population. Of course, we'd never be able to prove it one way or the other, but rather just 'spit balling' the likelihood.
EDIT: Just to extend the above... Plants, especially fast growing stem and floating plants will use ammonia as their nitrogen source. So in a heavily planted tank, there may only be a little excess ammonia for beneficial bacteria to process. But this is a good thing as it results in lower nitrates. So the amount of beneficial biology, regardless of bio-media real estate, is less.... but who cares?