Besides storing the value, saving either field from the system Config page (super admin only) re-registers your site's webhook address and secret with Root Planner, so Root Planner knows where to send route updates. The first time this feature reached your account, Sprwt also ran this same registration once automatically, provided a Root Planner token was already saved at that point — it does not repeat on every later Sprwt upgrade. If routes stop arriving on the Sync Report after you rotate the token, re-save it from the system Config page to trigger the registration again.