The login block customizes the default login page to match your site branding. It should be used on the ‘Login’ pages configured under pages.
The Login block is located under the Widgets category in the block editor (unlike the other blocks).
Why another Login block?
The login block is somewhat different from the other block provided by Mindspun Payments. It even lives in a different category. There is already a core login/logout block that can show the login form.
So why another block? Branding. It’s important to give users a consistently branded experience on your site. To work with their account, users must log in. Without customizing the login, users get a generic login page that doesn’t look like part of your site.
The login block lets you build any styled login page you want instead of just using the default form layout (unlike the core block).
You don’t have to use this block—there are many other options for theming the login page. If you prefer one of those, that’s perfectly fine. Everything will work together. This block just guarantees that you have one way immediately available.