The designs are passable for a mobile version of a simple website, but really sub-standard compared to the average app on the Play/App Store, whether native (Swift/Kotlin) or hybrid (Flutter/RN). In B2B SaaS you can get away with the 5000th shadcn UI, not so much for B2C mobile. The days that stock Material UI actually saw usage there are a decade behind us.

If you have a tool/mode/prompt that creates good mobile UI designs, I'd love to know. Doesn't even have to generate code!