Why? Well like you say, "It depends."

There is certainly value in being able to save it, so I agree saving it for 5-6 years is probably more valuable for most people today.

But what if buying that food/house made a lasting impression on the next generation, and builds the foundation for it as is the money of the future? There is a degree of lasting value in spending it and building the tools, infrastructure, and mindset, so that it continues to be more adopted and valuable in the future. When should that transition price be paid?

I'm thinking that Gresham's law applies here, and it's what you are talking about. Using fiat money at this point in time for short term needs as long as it's accepted and saving their hard money would be far more beneficial for most people. And many have it backwards. We should definitely be thinking more about what is valuable and lasting.