IMO, for Model 3 owners who routinely drive in areas where Tesla roadside service may take a long time to arrive (same applies to AAA roadside service), and availability of a Tesla loaner wheel is uncertain, then run flat tires are a valid option (of course keeping in mind their typical 50 mile range limit). Peace of mind is worth something. Each owner has to decide if it's worth range trade-off.
Also, one should consider range reduction due to run-flats vs. range reduction due to added weight of a Modern Spare-type wheel kit. I don't know the answer to this, but it's worth investigating.
No matter what, it's worth upgrading to AAA Premier to get 200 miles towing.