Taking a virus and ‘aging it’ a few generations - so we can see what it might evolve into in our lifetimes or our kid’s is one thing - - with the goal having a workable quick vaccine if necessary - makes sense. COVID was ‘aged’ hundreds of years - - in short moving into a bio-weapon range.
Sure, but it’s the same mechanism in both cases. The only real difference between “gain of function” and “weaponization” is a quite subjective one, the intent of the researcher. Unless the researcher working on weaponization is very stupid, they are not going to leave much evidence that their intent was anything other than to “help develop treatments for future pandemics”.