Would you use an iOS app like this? Weight history tracker focused on data ownership & no lock-in

I’ve been building an iOS app concept called LegacyWeigh and wanted to get some honest feedback before I go too deep. Most weight/fitness apps I’ve used feel either ad-heavy, locked into their ecosystem, or only show you a “snapshot” without making it easy to look back years.

The idea: • Manual weight entry with dates (super fast logging). • Graph your history (line charts over months/years). • Set goals with progress indicators. • Import/export via CSV/JSON → so you can always take your data with you. • Privacy-first: no ads, no forced account, all data stays local unless you choose to sync. • Premium tier: multi-device sync + unlimited exports (something like $4.99/mo or $49/yr).

Target audience: anyone frustrated by switching apps and losing their long-term data, or just wanting a lightweight, private way to track weight over time