Discovery and browsing are not good on the assistant interface but I'd argue that's a constraint of voice vs visual. On a desktop/mobile, the screen holds the state so you can go back to previous entries, etc. Over voice, you mind holds the state which scales much much worse.
To the credit of the Shortcuts team at Apple, being able to visually select and define certain phrases for commonly completed tasks is helpful in this regard, but I’d guess only a couple % of the user base is even aware that Siri Shortcuts are possible.
Is this just normal phone Siri or HomePod Siri?
Normal phone Siri. Not sure if it works for the HomePod