A few tweaks that I think would make a difference:
It’s confusing that the default category is “Don’t translate.” It would be better to hide this category if we aren’t supposed to translate it.
It would be helpful to be able to choose categories to hide myself. There is a lot of material I have no intention of attempting to translate: lessons, welcoming messages, promotions, and so on. Arguably none of this is UI, but I understand that it has to go somewhere.
An attempt to partially categorize the large number of uncategorized strings would be a helpful motivator.
