Question about Joseph Joseph Recycling Station Titanium

And if you can't fill the bag completely and have to take it out first .... then isn't the whole point of this bucket missed? Somehow I don't seem to understand the concept.

Yes, it is compatible. But you can't fill the bag completely. For that, you have to take the bag out at the end.

90l bucket with 60l bag fits into 35l Zürisack ... huhhh? How does that work together?