Depending on the services you expect the ER to provide, that seems reasonable but an ER (in the sense understood in 1st world) could be overkill. Bear with me.
If reliable, speedy transportation to the mainland is available, properly trained paramedics/nurses/doctors can (generally) stabilize patients for transport to a better equipped medical facility.
In the long term, yes, ER for sure. There are many life-threatening emergencies where time is of the essence - no argument there. But it seems this project is starting pretty much at square one so from a financial (and health care) standpoint, taking full advantage of resources that already exist seems to be the correct "baby step".