Is Kurzgesagt losing their edge?
They released this rather, IMO, paltry video.
I can think of a couple of reasons off the top of my head alone that they could had touched on, from the concrete to the more whimsical:
1) Putting people on a whole other planetary body pushes the envelope and application of engineering and science in so many fields it can sustain a economy all by itself, not to mention the advances thereof. Environments, Biology, Medicine, Engineering, Astronautics, etal. The only way to know how mankind will survive or live in space, or the Moon, or Mars, is to keep putting people there for years or decades on end.
2) To keep mankind and the Gaian Biosphere intact in some form elsewhere. This is what Zubrin calls 'spreading the eggs out of the basket' or 'not keeping all of your eggs in one basket' scenario. It is a response to the reality that we're in a system with two or three debris fields in a violatile and active universe that can fry our planet many times over - and has. It is not very glorious or glamorous, sure. it is very hoo-hum, and ties into 1 hard, but it 'works'. Scenarios such as global warming or nuclear war do not tie themselves into this much; as earth will still be very habitable after the worst of global warming and any nuclear war has the potential to hit any colony - this is against natural astronomical disasters; and it does have a vague asterisk that demands mankind keep spreading itself and the gaian biosphere to 'be sure'.
There's a 2.5) where the pressures of these new environments will, over time, keep the diversity and adaptation of the biosphere and mankind 'going'. The Humans of Tau Ceti may be, eventually, by nature be different from the Humans of Mars or Earth, and this is not a bad thing by itself.
3) The same reason Chile and Argentina have 'towns' (read: Hamlets) on Antarctica: Nationalistic Pride. Nations, as groups of people, engage in dick-waving; as Earth is settled and cultured, the way to show that your nation is 'great' is to march outwards. Orbit, the Moon, Mars, and beyond can simply be reached by giving the Napoleon Complex of the Nation a sustained kick for a few decades. India wouldn't be looking at Space if China wasn't already frolicking around there, and China went to make up for their century of humiliation and to show the world they can keep up with the Russians and Yanks, who went up to basically provide a cover for their missile programs....
4) More fanciful and basically worthless excuses, which is what the video provides - that someone, eventually, wants to do it and will. Self-glorification might tie into 3) a bit, or allure to some persistent libertarian-space-future myth where big heroes like Musk use their billions consecutively for decades to make private space programs and the like all to make their mark on history. Included in this are 'economic' reasons (Even Zubrin falls to this, claiming that just because Apollo inspired a generation of technology, science, and engineers that such will continue to happen if manned missions continue and all the economic benefits thereof), or utopian ideas that mankind must continue to spread from a stagnating, cultured Earth to keep pushing itself (Zubrin again tries to paint Mars as some pioneer paradise where a polity can start again with modern, updated ethics free from the chains of Earth ones akin to how the US did away from the UK, or so on).
What do ya'll think?