Memoto is a service where the photos from a lifelogging camera are organized and made searchable in an app in your smartphone. The cloud, no matter if you embrace that term or not, is inescapably needed as part of our tech chain. I think you would agree that data stored locally will always be a nuisance to make available in your phone without synching to cloud servers. What we provide is an option for you to keep a local copy of your photos, no matter if you synch it to Memoto Secure Storage or not. None of the functionality provided in our app will still work if you disable synching to the cloud.
We are receiving a constant stream of feature requests supporting different use cases. At the moment we focus on functionality that supports as many use cases as possible. To provide the same functionality with local storage would mean to duplicate everything we have developed into standalone software, and then support that forever.
Regarding the privacy aspect, if we allow third party apps to integrate to our API, we can allow the user to retain control over what those apps have access to. But if we would chose to make a development effort to allow locally stored data to be used as an integration point for third party apps, we can no longer provide that level of control. An app that turns out to be malicious can't be disabled across the entire user base, because it's probably installed as an executable on local computers.