Is a CPU reball just a "Hail Mary" guess, or a legitimate permanent fix?

Is a phone CPU reball just a last-resort guess for a technician who can't troubleshoot the root cause of a problem? I frequently watch CPU, RAM, and storage reballing videos online, and I'm curious about how long these repairs actually last. Recently, I watched a technician on YouTube heat up a CPU to temporarily power on a phone for data recovery. It died immediately afterward, and he concluded it was a definitive CPU fault.I wonder how long can this reball fix hold?