This is true. The easiest way to make this clear to someone is to ask them to define 'value', and note that they can't do so without either a) talking in terms of people and their subjective beliefs or b) relying on words that are just synonyms for 'value'.
You can avoid talking about people's subjective beliefs about good or services, and instead talk about their subjective beliefs about their lives. You can then measure the curve of subjective satisfaction with their lives and value can be defined as "the impact of a good or service on the satisfaction curve of a recipient's life".
Tying value to the subjective experience of the outcomes is qualitatively different than tying value to subjective beliefs about the goods or services.
For example, someone might buy a million dollar McMansion because they subjectively believe it's valuable to them, and then discover that they're miserable in it because it's horribly designed, poorly constructed, and expensive to maintain. That's fundamentally different from someone who buys a house that is cheap to heat and cool, makes their everyday tasks easier, and causes the release of pleasure chemicals in a sustainable and helpful way.
The latter has intrinsic value in a way the former doesn't.
Edit: You can also define value as the ability for a good to increase your overall wealth. So, some goods have a cost, and do nothing to my net worth (lottery ticket). But some, if you look at the longer term, have a cost, but also add to my net worth (buying a soy milk maker). If you put a dollar value on your experiences, this can cover everything.
