The tool is pretty good, but there are two things I would find useful. First is ability to add file from your computer and the second is possibility to display some explanation for the strings. Some of them can be difficult to translate when taken out of context so you have to check it inside the app. I'm not sure if that function would make sense though as the explanations would probably have to be written in the strings.xml file, making it bigger and harder to read.
PS. Also noticed one small mistake - it says "translac
tion" instead of "translation"