Perplexity on mobile
Perplexity is useful on mobile when you are checking a fact, comparing a product, finding a source, reading a quick explanation or asking a current web question. The source-first pattern is convenient because you can open links immediately.
The limitation is that mobile research can still be shallow. If the topic matters, save the source links and review them on desktop before making a decision.
ChatGPT on mobile
ChatGPT is useful on mobile when you want a general assistant in your pocket. Typical mobile tasks include rewriting a message, asking for an explanation, drafting a reply, brainstorming, checking code logic, understanding an image or turning a rough idea into a plan.
The limitation is source confidence. If the answer depends on current facts, ask for sources or use a search-first tool before trusting it.
What to check before choosing
Check whether the mobile app supports the features you actually need: voice, images, file upload, history, projects, model choice, search, sharing, privacy controls and cross-device sync.
For business users, also check whether mobile use is allowed under company policy. Sensitive customer data, internal documents and confidential screenshots may require enterprise controls.