They are not talking about doing away with dates altogether, just replacing the "best before" which gives an artificially short shelf life with "use by". At the moment, food that is perfectly safe to eat, is thrown away because the manufacturer claims that it won't be at its very best after a certain date. Just as an example, a loaf of bread with no preservatives is at its best for only a single day, but is quite edible for anything up to a week (or even longer, depending on how it's stored).