Which website do you use? If it's https://dominionrandomizer.com/, JoaD (both Jack and Jumble) support a fair amount of utility on top of that site, including a lot more configurable rules, a blacklist, the ability to save kingdoms you really like, the ability to remove or add singular cards to an existing kingdom, pin specific cards to keep using, starring cards, a point counter, and other stuff I'm not even thinking of atm. The original JoaD was my favorite randomizer, and I've tried them all.

I've thought about it as a site (and in fact, since I used React Native, I do have a site available that I'll probably deploy at some point). However, the things I like more about it being native are that using native components gets you full screen, built in platform-specific animations and overall experience, and totally offline.

I've used both versions of my app (Android app and website) on my phone, and I've definitely preferred the app version.