Ignoring the baseless speculation on whether these are legal guns or illegal guns, since there is a pretty good spread on that spectrum:

The importance is having fewer guns overall. If the availability of legal guns is drastically reduced then it will be a lot harder for an ar-15 to fall off the back of a truck or go missing in someone's home. It won't happen overnight but it will happen pretty quickly. We have seen this happen in other "Western" nations.

Personally? I don't want to infringe on the rights of responsible gun owners. If anything, I want to make them even more responsible. What that means is that I want:

1. Much stricter background checks on buying firearms. By all means, factor therapy and rehabilitation into that (just because someone had a nervous breakdown in high school shouldn't impact their ability to own a people killer so long as an accredited mental health professional signed off on it. But no "gun show loopholes" and more "cooling off periods" to ensure that NOBODY can buy a gun same day.
2. Ammunition is a controlled substance. You want to buy a box of 9mm rounds? Cool, you are going to fill out a form to make sure that is tracked and you are going to be limited to a certain number of rounds per year unless you fill out the proper forms to get more (comparable to how suppressors and SBRs are handled). And, again, cooling off period. You fill out the form and a week later you can buy your bullets.
3. Liability on firearms. If your gun is used in a crime then you are charged for it, regardless of whether you pulled the trigger or not. You can bet that people will be disposing of their twenty kitchen cabinet guns almost immediately once they realize they are liable for Little Timmy shooting up his school. And if a gun goes missing? You can bet they will report that within minutes of finding out (and will be checking those gun safes semi-regularly as a result).
4. Liability on sellers. If a gun is used in a crime then ALL the above paperwork will be triple checked and any improper procedures will result in the seller losing their license or even being charged with negligence.

All these giant piles of "illegal guns" will dry up pretty quick (comparable to a civilized nation where they are fairly rare for criminals to use) and all the guns that kids take to school will similarly actually be locked up in a way that Little Timmy doesn't have unsupervised access to.

But all those Responsible Gun Owners(TM)? They won't be affected because clearly they are already securing their firearms when not actively in use and always know where their collection is and are making sure that only people who are also Responsible Gun Owners(TM) have access to it.

Hell, as a treat, let's let people who own public shooting ranges jump through some more hoops to relax some of that. You need 500 rounds of .223 a day to practice shooting? Buy it by the mag at Herman's Military Antiques and use it at his range. You can't take it home with you but you never needed to take it home to practice shooting, right?

But also? Public shooting ranges. no private ranges or members only rangers that let rich youtubers build up an armory. If you want the exception then you have to admit anyone who can pass a safety check (with strict penalties for those who inevitably lie to keep The Pink Haired People out) and have documentation that they are using a legally owned firearm.