You know, firearms in general have been a hobby/interest of mine since I was a kid. And to be perfectly honest, until the Vegas incident, I'd never even heard of bump stocks. Now that I've been educated on them, I tend to agree with you. They have no viable reason, other than for someone to profit from selling a relatively useless novelty item, to exist.
I loved firearms when I was young. Still do, but haven't owned or fired one in a long time.
I was given a WWII Enfield when I was a remote rural child. The local rabbit population took a huge hit that summer. I had good times during the Great Leporids Holocaust.
I loved that rifle. She had a name.
Hunting was a big part of my familys life at that time. It provided a substantial portion of our food, and some income.
So I believe I can relate to both sides of the debate.
And as is so often the case, I think it can be summed up with "all's good in moderation".
At one end is no guns, at the other is all guns. I think we should be somewhere between the two. Guns, but with reasonable restrictions.
There will always be a debate about where that line should be, and I'm ok with that.
I don't really see it the same. I get your point, banning the bump won't stop attacks. But it can have an effect on how successful a killer can be.
The thing about bumpstocks is that they have no use or purpose other than killing large numbers of humans.
A bump stock has no use for hunting or sport. It lacks the accuracy necessary.
I'm not a fan of gun control as a fix for mental health issues, but I can't defend an item that has no purpose other than large scale murder.
For the same reason I support restricting assault rifles, and any item that was designed for the sole purpose of killing humans.
A car is not as effective. A vehicle is only deadly when the killer has the surprise. It is very easy to avoid a vehicle if you see it coming. A spray-and-pray rifle is still deadly even when you see it. So while vehicles can be very deadly, they are not usually as effective, and are always easier to stop.
When looking at the Australian statistics, after they banned guns, knife attacks increased roughly the same amount as gun attacks dropped. Which might seem to support you point, except that the number of deaths did noticeably drop. There was still just as much violence, but it was no longer as effective.
I still support people having a right to possess dangerous objects, if there is a possible reasonable use for them. But when the only use is killing, I view it the same as things like Zyklon B, or radioactive waste. They present only danger, and bring nothing of use.