[eduction]

>the order of the key and value can be reversed

This is the case with any hash-map in any language, modulo some of them making certain keys illegal.

But "string":"string" can be reversed in pretty much any language's hash-map.

>here's no way to tell at a glance what e.g. the value associated with:bar is.

You've certainly constructed and formatted a hash-map that is a little tricky to understand, but 1> this combination of key and value types is going to be pretty rare in the wild and 2> to the extent it exists, people would format it to be easier to parse, either by adding commas or newlines.