From what I gather after scanning this document, speed orders provide results that the national team coaches can use as additional criteria when they select their rowers for championship regattas. This reminds me of the dreaded Dodge Ball Selection Process in elementary school. You remember, I KNOW you do! The gym teacher would appoint two classmates to select the teams, and the rest of us would stand around, afraid to look at each other or them, afraid to seem too hopeful, trying to look both nonchalant and athletically powerful, and dreading the prospect of being one of the last two standing...
The "selectors," savoring each delicious moment of tormenting their peers with the teacher's approval, evaluated us using a series of questions like this:
"Who won a speed order?" would be to rowing like adding: "Who won the last time we played?" to the list above. The similarity is a stretch because in elementary school, who's the cutest and most popular were probably at the top of the list depending on the selector, while in national team selection, the criteria is designed to eliminate such pre-teen subjectivity.
To sum up, a speed order provides coaches with additional statistics with which to evaluate athletes when it comes to choosing who will compete.
Corrections are welcome!