I thought this would be extremely useful, but it totally fail.
To begin with, the app was very slow to load.
I tested the app by creating a small image of some text on a webpage (This app's own description). There were five short lines of black text on a white background in Segoe UI14px.
I selected the correct language (English) and "Text Only" conversion. The conversion took a long time to complete, pausing at 60% for several minutes.
Results: The conversion contained inaccuracies.
It can't be said that I wasn't giving the app a chance - The app was tested on an eight-core PC with 16GB RAM and 80Mbit Internet connection.
By contrast, I pasted the image into OneNote, right-clicked on the image and selected "Copy Text from Picture" and then pasted the text into OneNte. The OneNote approach took less than 5 seconds to complete and the results were better.