Hypothetically, it would eliminate the chance of failure and the requirement to methodically plan ctb. Which is a win for people that don't mind the possibility of additional suffering and only care about failure chance.
It can't be better than if there was a painless, reliable, affordable way to ctb. I think of assisted suicide, like Dignitas but affordable & available for everyone.
It's a good point that attempting suicide can already mean you lose your liberty.