SpaceX is known for preferring reusable parts whenever possible. Before the crew dragon incident, where a leaking check valved resulted in a plumbing explosion, it was determined that the check valve be replaced by a burst disk, which is not reusable. In fairness, the engines on the Crew Dragon are no longer going to be used for propulsive landing, and instead will only be used for emergencies, why didn't SpaceX decide to use 2-3 check valves instead? Doesn't this means that the Super Draco is no longer has multiple-restart capability?
Some basic statistics shows that using 2 or 3 already makes the probability of this even astronomically unlikely, and it would enable the possibility for engine re-ignition.