What is the difference between observable.map and proxied observable?

[Zzzen]

observable.map

Creates a new observable ES6 Map based on the provided initialMap. They are very useful if you don't want to react just to the change of a specific entry, but also to their addition and removal. Creating observable Maps is the recommended approach for creating dynamically keyed collections if you don't have enabled Proxies.

IIUC, proxied observable can track addition and removal of entries.

[urugator]

Proxies are only relevant for plain object and array. The difference between observable Map and (proxied) observable object is the same as difference between non-observable Map and non-observable object. Both support dynamic keys.
Non-proxied observable object does not support addition/removal of keys using assigment/delete operator/Reflect.*/etc, but it's still possible using collection utilities.