Wiggling is down to lack of precision and lack of subpixel rendering, unrelated to Z buffering. Z buffers are for hidden surface removal, if you see wiggling on a single triangle floating in a void, it's not a Z buffer problem.
When you see models clipping through themselves because the triangles can't hide each other, that's the lack of Z buffer.
Thanks for clarifying. I knew I was getting something wrong, but can never remember all the details. IIRC PS1 also suffered from render order issues that required some workarounds, problems the N64 and later consoles didn't have.
Wiggling is down to lack of precision and lack of subpixel rendering, unrelated to Z buffering. Z buffers are for hidden surface removal, if you see wiggling on a single triangle floating in a void, it's not a Z buffer problem.
When you see models clipping through themselves because the triangles can't hide each other, that's the lack of Z buffer.