A lot of indicators of wellbeing at least correlate well with GDP and tackling climate change will need resources.
GDP isn't even measured the same across different economies. GDP does not include negative externalities, and GDP increases if a country goes full-on war economy. It's scary to see that number being used for things it doesn't even measure.
I have no idea how that relates to my empirical point (nor does it refute it, other than, yes, there are finer points about normalizing things across countries, per capita etc.).
To put it perhaps oversimply: because growth isn't just more stuff produced the same exact way, it is also better stuff in new ways. Look at the GDP compared to a bronze age civilization to modern times. We didn't achieve that just by herding more goats and forging more bronze, although we have far more of both goats and bronze thousands of years later. Most of it is in things that money flat out couldn't buy in the past. Just antibiotics for one, let alone more complex medicine and services.
That's an easy thing to say from the comfort of a developed economy, not so easy for the developing world. Economic growth is what provided the standard of living in the developed world, which is much greater than pre-industrial revolution.
For economists, growth is shorthand for growth in (inflation adjusted) GDP, which is the sum of all incomes. Most adults who pay their own bills find it rather obvious why we should care about income growth: it pays the bills, and hopefully leaves some extra to enjoy nice things and retire at some point.