Quick answer: Use cloud AI when you need the largest model, live web access, or heavy reasoning. Use private local AI when the prompt contains personal notes, screenshots, drafts, work ideas, or anything you would rather keep on your own device.
Cloud AI is best for maximum capability
Large cloud models can be very strong for complex reasoning, web-connected tasks, and long context workflows. If your task depends on live search, huge context windows, or the most capable model available, cloud AI can be the right choice.
The cost is that your prompt normally leaves your device. For many everyday prompts, that tradeoff is unnecessary.
Private local AI is best for sensitive everyday context
Local AI Chat is designed for prompts that should stay close to you: personal notes, rough drafts, screenshots, private questions, study material, and work ideas that do not need cloud upload.
This is the real value of local AI. It lets you use AI in the same place your private material already lives: your iPhone or iPad.
Local AI also works when cloud AI cannot
Offline AI is useful in airplane mode, during travel, in weak-signal areas, or when a network blocks AI services. Supported Local AI Chat models run on device after the model files are available.
Privacy is not only about secrets
Most people think privacy means passwords or medical documents. In practice, small prompts can still reveal a lot: what you are studying, what you are worried about, what you are building, where you are traveling, or what you are drafting before it is ready.
That is why local AI can feel calmer for everyday work. You can ask rough questions without deciding that every half-formed thought should become remote service input.
The practical choice
Use cloud AI when you need the largest possible model. Use Local AI Chat when you need a private AI assistant for everyday mobile work without an account, API key, or constant internet access.
Simple rule: If you would hesitate to paste the content into a random website, try local AI first.