Ramp rate as determined by training stress, which is determined by NP as it's related to FTP, which may or may not be accurate depending on workouts you're doing (NP busters, etc)? Or you can, you know, just do a little self-evaluation. I feel like ****, maybe I need a rest... I feel great, let's keep things rolling. Common sense stuff.

Phenotypes like if you're a time trialer or a sprinter isn't determined by sFTP and is determined by types of workouts/efforts you're doing.

Strengths and weaknesses against the world is called racing and/or group rides and is not determined by sFTP.

I don't think changes in FTP really matter that much. Like I said, complete the workout or not. Adjust accordingly. CP values for long-term comparison make way more sense.

Changes in W' or Pmax. Ehhh, back to competition and also not determined by sFTP.

If that's the argument for needing an accurate FTP number, ehffh. Most of those aren't "post-ride analyses" that are dependent on a particular FTP number in any case.

And still, I question the "performance" part of those metrics. More amounts to lots of graphs 99.9% of people neither care about nor utilize. I look at performance as CP or speed or actual race/ride results, which I imagine/know most do.