we often want to show 2 metrics in the same graph (especially in dashboards):
1. how many files were opened?
2. what was the fail rate opening files?
right now we can't product such a card, because only metric #1 will be visible (metric #2 will be a % and hence much smaller) . to show the 2 metrics on the same timeline we need the ability to set one of them on "right y axis"