I've been using the Memos on iOS (https://memos.org) for searching. Memos additionally lets you copy the text and is on device.
But the web site is one page, without even an "About" section. All it has is an animation, some text, and an e-mail address. No information about the company at all. Even the whois for the domain is hidden.
For the sort of person for whom "on device" processing is important, information about the company has value.