A tipless knife may prevent accidents, but if you purposefully tried to stab yourself or someone else with one of those knives, do you honestly believe it wouldn't tear right through your flesh? Neither my butter knives or bread knives have tips, and yet I could easily stab people with them.
FWIW the data suggests that thin cotton clothing can stop these knives much more effectively, and therefore could at least make impulse knife crime (indoor assaults) much, much less deadly.
https://www.independent.co.uk/news/uk/home-news/rounded-knif...
Let's Be Blunt have more data: https://www.letsbeblunt.co.uk
I don't really find anything in those sources convincing. One is a researcher for an anti-knife crime advocacy group that makes vague statements about how it will reduce injuries, but don't specify how much, and says their research still needs to be validated before publishing. And the other stuff is just statistics of how many people get stabbed with kitchen knifes with the assumption that if everyone had blunt knives instead that either less people would be stabbed or their stab wounds would not be so serious, which is the point I find suspect to start with.
Yes if you wear enough cloth it can block blunt stabs okay, but I very much doubt peoples regular clothes are going to do anything except drag some dirty cloth into the wound unless they walk around with thick work bibs on all the time or 3-4 layers of denim. And even that is still very limited protection to someone actively trying to stab through it. A screwdriver is even more blunt than these blunted knives and it would have no problem going through any clothes except maybe a reenactors linen gambeson.