Yes, travel insurance is worth having for a trip to Puerto Penasco, a Sea of Cortez resort town that draws huge numbers of visitors driving down from Arizona for a weekend on the water. The honest reason to carry cover here is less about the town itself, which is fairly low-risk as Mexican beach destinations go, and more about the boating, fishing, and long desert-highway driving that fill most itineraries. A policy still smooths over lost luggage or an unexpected pharmacy run, on top of covering the activities that actually bring people here.
Puerto Penasco has local clinics for routine treatment, but anything serious is generally referred within Mexico or, for many visitors, evacuated back across the border to Phoenix or Tucson, the nearer major medical centers for most drive-down travelers. Confirm your policy covers cross-border medical evacuation and transport rather than only local treatment, since that transfer is the part most likely to involve real distance and cost for a US-based visitor.
Boating, sport fishing, and diving in the Sea of Cortez are the main draws around Puerto Penasco, and each carries its own real risk on open water far from a clinic. The eastern Pacific hurricane season, roughly May through November, can bring storms up the Gulf of California that disrupt boat charters and coastal plans with little warning. Remember, too, that Mexican auto insurance is a separate requirement from travel medical cover if you are driving down - one does not substitute for the other.
Keep any clinic paperwork, boat-charter incident reports, and receipts for treatment or vehicle recovery, since claims tied to a self-drive, water-based trip need clear documentation of what happened and where. Check whether your existing health cover extends abroad and specifically to Mexico before assuming it does, and confirm your policy's claims process before a Puerto Penasco weekend rather than during one.