In the discussion about building a micro combustor, the main focus is on finding an affordable catalyst for the combustion of gaseous hydrocarbons like methane and propane at atmospheric pressure and temperatures below 200°F. The complexity of the question is highlighted, as the efficiency of a catalyst depends on various factors such as surface area, intrinsic reactivity, fuel and air flow, and equipment design. Suggestions include exploring hopcalite as a potential starting point and considering metals from the platinum group, such as palladium and ruthenium, despite their high costs. The conversation also touches on the characteristics of platinum group metals, emphasizing their role as effective catalysts for oxidation reactions.