[ASK PH] Do you need an app which cannot STEAL or SELL data?

Hello everyone, Sometime back I was talking to a friend in my company, and he was expressing his discontent with his job and why he wanted to start his own bootstrapped startup. He told me that he lost his personal diary where he used to write lot of ideas and suggestions for all kinds of apps he has been using on his macbook. I asked him why he doesn't use an app to save all the notes online. He said he doesn't want his data on cloud servers and potentially being hacked or being read by a person, as he believed most app owners can read the data if they want.  Now, an idea struck to me, for all the power users of internet like us (entrepreneurs / SAAS owners / single founders / bloggers / indie hackers), our work data is super critical whether its in note application, or project management or docs or its an app connected to our facebook account, google analytics etc etc. There are so many types of integrations or data that we  might want to keep private. Now what i am thinking is, why not create an app where there is 0 (Zero) data going out of the app. Not even analytics, not even heartbeat api nothing. So there is not even a chance of the developer reading it or some hacker exposing it etc. We would feel 100% safe using the app, I don't remember when was the last time even I was not thinking about developer watching over my data when trying out a new app. For some kind of apps, we can find an option like a note taking app which is client side encrypted before syncing, but not all kinds of apps like spreadsheets, project management etc.  So my quick questions to all of us: 1). Do you feel same way as my friend. (i.e Do you feel sometimes a need of apps where all data is guaranteed safe, as there is no network calls so not even possible) 2). If you want such apps, would you need data backup then? Like complete clientside-encryption or download-as-zip or backup to own google drive etc.  3). What kinds of apps you would want under these (Zero network calls i.e No Api Calls) guarantee?  Note taking, Project Management, Todos, Spreadsheets,.... 4). Would you be willing to pay for it? Or you want it to be free. (If free then how can I earn as there is no data to be sold also :D ) Somehow I feel excited to build such apps. Maybe a series of apps or a super app with this privacy guarantee. But would like to have an open discussion here first, maybe it was a dumb idea all along. :D  I have created a survey specifically for voting on which app i should start with, here: https://www.supermakers.club/vote-for-safe-apps/