Firstly, it allowed Sainz to rejoin the race in his original third-place grid position after a collision with Piastri at the first corner had caused a puncture which led to him going straight on at Casino Square.
And it allowed Ferrari and McLaren to switch their cars to hard tyres while the barriers were repaired, with the expectation that they would run and run and perhaps have to get to the end if there were no more safety cars.
That meant taking the tyres about 15 laps further than Pirelli had predicted they would last, but Leclerc and his pursuers were more than capable of making them last by virtue of careful driving and controlling their pace.
The teams spent the race looking at gaps to rivals and wondering about pit-stop windows but the remainder of the grand prix passed without major incident and going to the end was what they were forced to do.
In the closing laps, Leclerc underlined his domination of the weekend by stretching out his lead and he crossed the line seven seconds ahead of Piastri.
Leclerc screamed with delight on the radio after crossing the line, before saying: “I need to cool down, myself as well. Tonight will be a big night.”
His engineer Bryan Bozzi said the team would stay in Monaco with him to celebrate. “You’d better,” Leclerc said.
He added after getting out of the car: “No words can explain that. It’s such a difficult race. The fact that twice I have been starting on pole and we couldn’t quite make it makes it even better in a way.
“It means a lot. It is the race that made me dream of becoming an F1 driver. It was a difficult race emotionally, already 15 laps from the end I was hoping nothing happened.”
And he said his thoughts had turned to his father, who died in 2017 before Leclerc had made it to F1, in the closing laps: “I have to admit that I was thinking about my dad even more than the driving, he gave everything for me to be here.”
If the race for the win was sufficient a demonstration of the difficulty of passing at Monaco, Verstappen put it in even starker perspective after rocketing up to Russell’s tail in the closing laps, before being unable to make any progress.
Verstappen’s sixth place combined with Leclerc’s win cut the Dutchman’s championship lead to 31 points after seven of 24 races, but both men had already emphasised on Saturday that the championship was long and no conclusions should be drawn at this early stage.
RB’s Yuki Tsunoda, Williams’ Alex Albon and Alpine’s Pierre Gasly completed the top 10 and took the final points, even though Gasly’s car had to be repaired in the red-flag period after a collision with team-mate Esteban Ocon at Portier.
Ocon was penalised 10 seconds for causing the collision, which will be converted into a five-place grid penalty at the next race in Canada.
No blame was attributed by the stewards for the Magnussen-Perez-Hulkenberg collision.