Why POST instead of PATCH when updating an article. Topic 5.12 Using partials to clean up duplication in views

This question is to understand the strange fact that for one situation it is necessary to informe the path, in form_for, and in another time it is not necessary, but stil works.
Before using partials the form_for were diferent from edit and new forms.

New Article

<%= form_for :article, url: articles_path do |f| %>

Editing Article

<%= form_for :article, url: article_path(@article), method: :patch do |f| %>* It's dificult to understand the diference of them and the use of method: :patch or even url: articles_path, once both are unified by using the partial _form.html.erb. What is strange too is that the resulting html form into the browser for both use the same action 'POST'. Shouldn't be PATCH or PUT for the **edit** form instead?

What is not clear too, is how does the _form.html.erb produces diferent paths once the code is the same.
What I think that would explain is:
1 - For edit, an existing object is sent to the form. For new a new object is sent and this one was not saved yet.
2 - Considering item 1 as true a new object, references/has/generates an url diferent from an existing according to its “age/status”.

Am I wrong?