I'd agree, except that natural gas isn't available on some planets. And having oil but no gas (or visa versa) makes basically no sense. And, my Nauvis base uses natural gas for what you say it should be used for. I have a conditional logic which allows for gas to be used for bakelite in my base in a box too. But I found that on worlds with no gas, I needed an alternative, so I use one of the many algae renewable recipes to make formaldehyde to a minimum level and only allow gas to be used once it is at 1/4 of capacity. Before that it is reserved for manganese.
As for oil. Well... I guess that's why Base in a box took so long to make.... Yeah, it can be gathered, but it can be made renewably too. And I switch to the less efficient recipe which plows through wood via coal when there is a shortfall of oil.
It kind of doesn't matter. My design will just keep destroying the resources which are either full or unprocessable until everything is full, and then make landfill, and then destroy landfill if that gets full.