I am now trying to learn French, and I find myself searching to the most trivial sentences in linguee.fr. Learning grammar and vocabulary is one thing; knowing the idiomatic way to express one's message is an entirely different beast. Things that might seem obvious to a native speaker, e.g. the difference between "I'm fine" and "I'm good," are completely unapproachable for a non-native speaker for the first few years of using the language. Now that I am fluent in English, I would find this feature annoying. But I wish I had access to something like this 10 years ago.