It's well known that nobody will fix a sidewall puncture. With good reason, the sidewall is thin and flexes. Conventional repairs in this area are likely to fail.
However, in 3rd world countries, it's common to use an internal patch, generally hot vulcanized into place. But sometimes just a cold vulcanized patch (like a heavy duty tube patch) .
Done correctly, they do last, at least in 3rd world countries. But you must remember that they often drive 40mph max, not 85 like we do here.
A sidewall leak can be very rapid due to the thin nature of the sidewall. At high speeds, there is often not enough time to understand the problem and react properly. Across the median head on crashes are often caused by a front tire sidewall leak. Hence the requirement for tire pressure warning systems in all new vehicles. A left front tire with 15 PSI may still feel normal at highway speeds, and 5 seconds later, it's uncontrollable, as it pulls to the left, followed by an attempt to turn to the right. Due to no pressure, that rolls the tire, the driver turns harder without result, and the car veers into oncoming traffic.