More or less because the blanks give a more realistic recoil and the smoke whisps which saves on time and processing in post and you can see if the action works in real time on review.. and there are arguements that handling the real deal does actually add to the performance...

But like the standard done properly makes it incredibly difficult for injuries from weapons to occur. Consider that in 30 years the gun deaths in film plunged to almost zero *. There is way more production out there then there used to be and every scene where you see a gun being fired that is usually not one take and those takes were repeated over and over again. That's tens of thousands of safe handles over the years.

I don't have any issues with sets having or deciding to not have real guns but the real thing is that on a set that is doing the standard every weapon from barely looking like a gun at all rubber replica to projectiless gas powered airsoft gun are all treated as though they were real. When they are handed over you have to be shown exactly what they are and replica or not they can never be left unsupervised. They are always in authorized hands or locked up.

It's part of why this case is so important. Anyone with money can make a non-union film. The best practices transcend union borders because accidents made from cupidity and negligence should have consequences. You ignore the warnings then the consequences are yours. The discourse often frames this as a personal issue but it's a systemic one. Showing producers that being safe is a sometimes food is a dangerous precedent because the power they have over people is no joke.

• (if you exempt the guy who ended up blowing his brains out with a company weapon because he was playing around. These days the spiel actors get include the phrase "the force of blanks can still be deadly, keep clear of the muzzle and don't ever directly point them at another person at short range. )