I've got an iOS app but no watchOS app. I've got shortcuts that are donated and I'm also providing INRelevantShortcuts, some are date based and some are location based.
They *never* appear on the Siri Watch Face, even with the developer settings turned on to show recent items and 'force sync'.
Anecdotally, my Siri Face doesn't seem to display shortcuts from other non-Apple apps either - I saw one for Carrot Weather once but I have probably a dozen apps enabled in the 'show data' preferences for the Siri Face and I'm just never seeing them.
Just me?