The Duolingo English Test reports an overall score from 10 to 160 in five-point increments, plus four subscores: Literacy, Comprehension, Conversation and Production. The overall score is what most requirements name and the subscores are where a borderline application is decided.
Roughly where the score sits. Universities publish their own equivalences and they differ, so take the number from the programme rather than from a conversion chart. What is generally true: the range most taught master's programmes ask for clusters in the middle of the scale, and demanding programmes go higher. If your target says "120", that is the number — not "roughly IELTS 7".
Subscore minimums exist and are missed. A programme may ask for an overall score and a minimum in Production or Conversation. An applicant strong in reading and weak in speaking can clear the overall and fail the subscore, and that is the most common way a DET result is rejected.
Acceptance is per programme, not per university. A university that accepts the DET for its taught master's may not accept it for a research programme, and a country's visa rules are a separate question again from the university's academic requirement. Check both, on official pages, before you book.
The video interview and writing sample go with the score. They are unscored but they are sent to the institutions you choose, and admissions staff do watch them. Treat them as part of the application: sit somewhere quiet and well lit, dress as you would for an interview, and answer as you would to a person.
The practical advantages, stated honestly. It is cheaper than the alternatives, it is taken at home, and results come back in days rather than weeks. Those matter when a deadline is close. They do not matter at all if your programme does not accept it — which is the one thing to establish first.
Retakes. Results arrive fast enough that a retake before a deadline is often realistic, which is a genuine advantage over the paper-based alternatives. Check the test's own rules on how many you may take in a given period before you build a plan around it.