It is important to note that this is not a trade agreement, per se. It's a rule governing the application of taxes in both jurisdictions.
As Ms. Smith acknowledged a moment or two ago, the level of trade between countries matters, but it's actually more of an investment focus. That is to say, when you make investments there's income hopefully generated on those investments. These rules govern how much each country can tax the return on those investments. It can also affect people employed, moving elsewhere, or moving from one jurisdiction to another.
Trade matters, but it's less about trade than it is about investment. Investment can produce trade, but it's a secondary effect.