They believe that through this, they are reducing the risks of losing all their bitcoin should quantum threats be real in the future and their holdings get attacked. That is the only reason why El Salvador is moving their bitcoins and I believe this should be something we can all learn from El Salvador. Distributing your bitcoins in more than one wallets will save you in the future and El Salvador knows this.
The Shor's algorithm is real, so is the threat of quantum computing. However, the threat is not immediate, and even if it starts today, everyone will know this. Still, Bitcoin gurus are trying to make the system quantum-resistant, so it is a race between the good and the bad.
Will quantum computing win in the future? Well, time will tell. All I can say is that the resistant codes that will fight it will be in place over time, and the good will not allow the evil to continue exploiting the innocent unchecked. There must be a way, even if it's linking the Bitcoin system to an anti-quantum system protocol. Something must happen.