On my iPhone it works, and provides very decent performance. The only catch is that it needs pretty much the entire phone's memory to work - so if you switch out of it to another app and back again it resets the state and has to load the model from scratch.
I've been running it on an iPhone 15 using this app: https://llm.mlc.ai/#ios - App Store link: https://apps.apple.com/us/app/mlc-chat/id6448482937
The same team have an Android version too which I've not yet tried myself: https://llm.mlc.ai/#android
On my iPhone it works, and provides very decent performance. The only catch is that it needs pretty much the entire phone's memory to work - so if you switch out of it to another app and back again it resets the state and has to load the model from scratch.