Precisely! Since you can't know for sure the true wind direction without stopping the boat or using an electronic instrument, the best you can ever do is guess its direction. I know we all do this to some extent subconsciously. I *know* by instinct that I''m heading well off true wind and how to manage the boat in gusts accordingly. I do concede that we need to all be using the same definitions to discuss points of sail and Jake's example of rule interpretations/protests is reasonable.
At the same time, however, I find if diffcult to support references to the true wind when discussing sail trim amongst the on-board crew of a moving boat. I just want to know how the wind is hitting my sail cloth, regardless of my speed through the water. If we say we're on a board reach (with reference to true wind), then I need to work out my boat speed & direction & true wind speed before I can tell if my trim/steering is correct. If on the other hand, we say board reach (reference to apparent), then I know all I need to know to adjust sails/course for max performance.

Jake's diagram of the official points of sail is overly simplified, even for boats at monohull speeds. Take for example the boat on a beam reach. Are we to assume that boat is not moving, and so has its sails set at ~45 degrees to the true wind? If it is moving, then how fast with respect to the true wind's velocity? A better depiction for high performance boats would be to show typical sail trim angles for all true wind angles...but we'd need to account for wind velocities as well.