While it doesn't compare to grade separating rail crossings at grade there are a few minor benefits. The removal of level crossings can result in increased speed limits on that portion of the line. The current zone speed is 40mph, not including temporary slow orders for construction. It should increase to a 50mph zone, which currently starts just north of the station. Of course, considering the proximity of Agincourt station, it would only benefit express trains (there currently is one during the morning rush). As for trains stopping at the station, at least they won't have to "approach the crossing at a speed not exceeding 10 mph from a distance of 300ft until the crossing is fully occupied" anymore. No more worrying about the crossing circuit, just full speed away!
Then again, the time savings would only be maybe a dozen seconds or so (per southward train). Lastly there is the safety aspect. I'm sure the people on the train that got stuck at that crossing for a couple of hours after the fatality last year(or was it two years ago?) would of appreciated it, especially the operating crew. It was an accident and not the more common suicide, so a grade separation could have prevented that tragedy.
Still considering all that, it would definitely be a stretch for the government to suggest that it makes a significant difference in bringing all day service to the line.
While it obviously doesn't apply in this case/line, before HSR can be implemented on other lines, they would need to be completely grade separated. It would not be a stretch to say a similar project on such a line has a large future benefit, providing we ever see HSR in Ontario that is