If you care enough about the playability of your instrument to get one of the Privias compatible with this pedal, the upgrade is a no-brainer. Even if you only use the far right pedal, it's a huge upgrade in feel from the tacky footswitch-style sustain pedal included with the Privias.
Really solid base which stays in place without needing any additional non-slip measures, nice weighty pedals with smooth action. The only criticism I have is that the sensitivity doesn't live up to the otherwise impeccable accuracy of the rest of the Privia experience. I'm by no means an advanced player but it felt like it lacked the nuance of real pedals where you get different effects by pressing down at different weights. I'm not sure if this is a shortcoming of the pedal or the PX-S1000 itself, but either way it's a noticeable flaw.
Even with that caveat, it's an easy two-thumbs-up recommendation from me.