All the hip colonists will be sporting martian Ikea!
Also, note that just because something is ISRU doesn't mean that it's Earth input-free. For example, for polyethylene: with the exception of gas-phase polymerization (which the aforementioned system was not), your catalyst actually ends up in the polymer itself, and is thus used up (gas phase polymerization is more complicated, it's prone to accidentally turning the core of the unit into a big block of plastic if temperatures aren't controlled right ). Even in the case where catalysts aren't directly consumed, they often still need to be renewed or replaced after a given length of time. And other parts all have their own wear and tear that needs to be dealt with.
Soil bacteria take it out of the air and put it back. But also sometimes lighting does it thus.
You mean this? That's a betta splendens.