You hit the nail on the head : "Different situations"
There's no "hard and fast" rules for choosing as there's no real right/wrong answer - both products will handle what you want to do. It really depends on your "audience".
Do you expect users to be able to navigate their way around the data, creating charts etc gaining their own insights in a more self-service manner (Qlik Sense) or do you expect them to view it as a report where they make basic selections/filters and it's all a bit more "guided" (QlikView)?
The one thing I would say is Qlik Sense is nicely geared towards mobile devices and is probably the better choice if you want to focus on visualisations.
Just an opinion!
(There's also this handy thread: What is difference between Qlik Sense & QV Desktop client?