I'm no expert, but I'd imagine fully dropping the quotes wouldn't allow you to use the same syntax as a map/dictionary in Javascript, whereby the keys could be

I'm no expert, but I'd imagine fully dropping the quotes wouldn't allow you to use the same syntax as a map/dictionary in Javascript, whereby the keys could be [almost] any type, and string keys could contain characters such as - or even : which otherwise would prove ambiguous to a Javascript parser.