Stryd can be used for running with any 3rd party app like iSmoothRun on the Apple watch, or PowerDashBoard on the Garmin watches. In those situations, the 3rd party app can grab pace and distance and power from Stryd.
If you are hiking or walking with a 3rd party app, Stryd will no longer work reliably. Stryd will switch itself off to save power when your cadence drops below 130 SPM for a few minutes. This will mean that your 3rd party app can no longer get pace, distance, power, etc. from Stryd.
You can still walk with Stryd, but you need to use a Stryd app to connect to Stryd. We use special commands to keep Stryd awake even while walking or when you stop.