1. It has been useful so far as a challenge for technological development that finds other uses on the ground, and this is certainly not about to change;
2. It has been useful so far, in direct applications, and there are still direct uses to be covered (dangerous asteroid avoidance, as an example);
3. It tackles the SPOF we have as a species: living on a single planet;
But the more important one, for me, is one that is contestable. Space faring provides humans with an aspirational goal. Without a long term goal, we are reduced to either an hedonist life, or a never-ending struggle against entropy. We are better, as individuals and as a society, when there is something to long for in the horizon.
- geolocation (GPS, GLONASS, etc.) - communications (Starlink, Iridium, etc.) - earth sensing (weather, climate, etc.)
All of these are multibillion $ activities that benefit from lowered launch costs.
20 Inventions We Wouldn't Have Without Space Travel (actual post from NASA themselves): https://www.jpl.nasa.gov/infographics/20-inventions-we-would...