Is this shape not rather impractical? It may be more difficult to accidentally knock over, but you would also need to tip it back to a somewhat extreme angle in order to get everything out of it.
I think the design was originally intended for use on boats, and other places where tipping is a likely occurrence.
I think it’s for any motor vehicle where tipping is likely. See this page with all sorts of pictures and examples, including old packaging.
No way am I able to clean that without a bottle brush. I’ll sick to a standard mug.
This seems like the kind of thing you’d need either a dishwasher, or one of those cafe rinsers that spray water up into the thing to clean.
You’d never be able to get your hand into the corners.