Dead or not dead

Well, the dead phone came to life the day after I bought a new one. I probably would not have known had they not told me to erase all personal info from the dead phone before turning it in for trade-in value. It perplexed me because how do you erase something that is dead? Besides their reasons, I was not comfortable sending a phone with all the info intact through the mail to God knows where. So I tried again to revive it and I assume it needed a vacation because it started working. So I erased it. I reasoned that if it happened once, the dying I mean, then it could happen again so I felt better about buying a new phone. I do like the new one. It is the same brand- Pixel 3a. The features have come a long way in three years time. They rave about the camera on this one so of course, I will have to give it a run for my money.