I went into this cold, knowing nothing about Ulysses 31. Reading up on it online later, I learned that this pilot episode pretty much has the same plot and story as the first episode of the regular series. The main difference is that some of the character and equipment designs were changed.
This pilot episode was never aired, and was only leaked online many years later. Since it's essentially the same story as the beginning of the televised series, there really isn't any particular reason to watch this -- unless you are interested in seeing how the designs evolved between when Ulysses 31 was proposed (the pilot) and when it actually aired on television.