I don't think that we can perfectly know what the best use of a resource is. However, I think that we can often perform better than price does. For example, it would generally be better to allocate a unit of food to people who are starving than to people who already have excess food.

Note that in some cases that won't be the optimal way to distribute the food. For example perhaps the starving person is actively hurting society while the person with excess food wanted to use the food to perform research that promotes greater food production in the future.

However, taken as a whole, allocating at least some food based on need is going to perform better than allocating all food based on price.