There is absolutely no way that I would ever trust my life on those steps. The entire load is placed on the wooden block at the point where it has been drilled. If the block would begin to develop a split or some weaknessalong the grain at the hole, it would snap right off.

Also, when weight is applied, the rope (if it stays tied) will stretch to some degree, which could cause the block to tilt, slide or wobble.

Now, I've seen some bad ideas in my day, but this one takes the cake. That's a broken neck waiting to happen, IMO. I would respectfully ask anyone seriously considering this method to re-evaluate what they're doing.