Yikes, no. Other way around in fact! Observable errors mean that there is an actual error and triggers error handling to the user. By saying, that for example

Yikes, no. Other way around in fact! Observable errors mean that there is an actual error and triggers error handling to the user. By saying, that for example, a search for a user in a list returns no results is a 4XX you are implying that the path is an error when the response is in fact, valid and useful. More than that, you now have cross-wired a REAL 4XX error (for example the API URL was changed and no result will work to it) with this fun pretend 4XX concept that ends up confusing your error handling ('Endpoint cannot be reached with this URL.') with ('Your result has no entries.'). Finally, conceptually speaking, it's not a 404. The URL you requested was handled by the endpoint you intended to reach. That is the exact opposite of a 404 for example. To me, conceptually it's just not an error in most cases and even when it is, it's likely an error on the other side.