The devil is often in the details, so a bit of back story thinking can help. I keep in mind that there are many, many products on the market and many of them do what they say but it is also true that we can do the same without their product.
So this is part of the ad that I found:
Matrix™ is a high porosity biomedia that provides efficient biofiltration for the removal of nitrogenous waste. Matrix™ is a porous inorganic solid about 10 mm in diameter. Each liter of Matrix™ provides as much surface (>~700 m2) as 170 liters of plastic balls! Plastic bio-materials provide only external surface area, whereas Matrix™ provides both external and internal macroporous surface area. These macropores are ideally sized for the support of nitrifying and denitrifying bacteria. This allows Matrix™, unlike other forms of biomedia, to remove nitrate along with ammonia and nitrite, simultaneously and in the same filter.
Matrix™ is completely inert and will not breakdown. It need not be replaced. Since the majority of the bacteria are internal, Matrix™ may be rinsed when needed without damaging the filter. Matrix™ is compatible with all types of wet or wet-dry filters.
All okay and I buy into what they say but with added thoughts!
You are starting the game with some knowledge of the nitrogen cycle and how it helps. That is the "why" of adding fish slowly to allow the good bacteria time to grow and take care of the waste/ammonia. As the bacteria grow and increase the amount of ammonia they can convert, you are adding fish.
So the game becomes how to provide enough places for those bacteria to live and "matrix" sounds like it should do the job but then we need to ask deeper questions. The bacteria will like tiny little nooks and spaces where they can hang out but they also will be on every surface like glass, bottom, plants, etc. It's often the "slick" stuff we feel!
So when we have plants which use the ammonia/ammonium as food as well as giving tons more surface for bacteria, we don't really get into needing special stuff for housing them! All those tiny spaces in the filter media do the same, so just avoid washing it too hard until the good guys are really getting thick all over the tank ?
Kind of like buying bottles of water when the same stuff comes out of the tap? It's okay stuff but why bother---unless you've got some super important and odd reason to help them make extra money. Keep in mind it is kind of a new product and most of us have never used it.