I agree with with BrianP55 especially in a bare bottom tank or a heavily or overstocked tank w/ minimal substrate or decor.
Also, not all canisters run with a mechanical media upstream of bio. Eheim classics for example. In stock form they're run with ceramic rings first.
I used to feel the need for fancy bio medias, but in most cases, you can achieve the same result with sponge media in your canister. It's a mechanical and bio media all in one.
I've chatted with folks over the years who run all kinds of fancy bio medias and rotate portions out while boiling/cleaning the old with every canister cleaning.
I'm not saying that's wrong or necessary, but on the other hand, I've got bio media that's been in service for 8yrs and looks new.