The Z shot allows you to approach the next ball along the line of position. Of course this assumes your spin is accurate enough to land you on the right spot on the second cushion. An advantage of the Z shot for non-BIH play is that you can adjust the angle off the first cushion over a pretty wide range.
This is the sort of shot that would be a good challenge to have at a gathering of AZBers. We could each defend our own preferred choice. Shots like this come up every couple of months.
So you're saying that you have more control with a "Z" shot , with the cue ball going towards the 8 after the second rail is the better choice here? Having the cue ball following straight down to rebound off the end rail never risks the cue ball getting too close to the 8. It ensures a better control of the cue ball distance from the 8, giving you a better chance to stroke the cue ball. Plus no matter what, you have a way to get onto the 9. Hit the "Z" shot too firm, or hit the angle wrong and there's no chance to make the 8. That means no run out. Following straight down means you technically don't even need to hit a rail to have position. And have more room to land optimally since the cue ball isn't going towards the 8 ball.