So far ultra wealthy individuals have donated getting on for 1 billion Euros in re Notre Dame. Clearly a lot of very wealthy people want to use some of their resources to rebuild a church rather than do other things they think are less important. That is their choice and their right as owners of the wealth. In economic terms they are optimising their satisfaction by spending it this way rather than that.
Not everyone feels the same way about old buildings vs, arbitrarily, starving children. We could get all down on the ultra rich and say they are maximising their satisfaction the wrong way. But it is useful to know yourself and what optimises your satisfaction before condemning others for what optimises theirs.
Humans are all insular and feel more strongly about things that are closer to us. We each therefore have a priority list that is ours and ours alone based on personal emotions, experience and desires. A friend dies a natural death at the end of a full life and it hits hard. 5 people died on the UK roads yesterday and I doubt most people even knew, unless they had one of those close links.
So everyone makes those satisfying decisions differently. That is why lots of choice is generally the route to the highest overall optimising solution. Anyone who says differently is deluded and probably a Socialist.
Anyway we can now do a bit of economics and ask an interesting abstract academic question. Rebuilding a burned church in Paris equates to how many lives not saved elsewhere – to the people that care about the singed building?
We have a handy metric in the UK from the National Institue Of Clinical Excellence [NICE]. They are the ones that decide if you get expensive healthcare treatment or not. They say that a year of life is worth roughly £30-40k (In NICE terminology “A Qualy”). Average lifespan and what not puts a whole life value at about £3.5m. Call it Euros 5m to keep the maths easy.
Therefore rebuilding Notre Dame is currently worth 200 lives give or take. Which must implicitly make said rich people happier than if it were the other way round.