By default, every WordPress login screen looks exactly the same and most of the time that is perfectly fine, but there are cases where customizing the login screen with your logo should be considered.
Recently I created a membership option on a client’s WordPress site using the premium plugin WishList Member. WishList provides options for adding login forms to pages and widgets, but depending on your site’s design and/or front-end strategy, you may not have the ability or want to add a login form to a page or widget. On a different client membership site, we added a custom menu link “Login” that took you to the standard WordPress login screen.
Also, with Wishlist, when a sign in error or lost password request occurs, you are taken to the default WordPress login screen which could possibly confuse your site members.