I think the fact that "you're not around to experience it" is the tricky part of reasoning about the utility of suicide. Visualising walking away helps because it puts the more selfish aspects of suicide in stark contrast. If I walked away from my life I'd carry with me a lot of guilt and I'd have to live with the awareness of how my absence has affected others. If I kill myself, the primary advantage is that I don't have to experience that guilt and that, I think, makes suicide easier to contemplate than making a serious commitment to walking away. That's why I say if I'm not ready to walk away from my life (and face all the consequences of my actions), I'm not ready to commit suicide.