WooCommerce has changed to Woo.com.
Explained as a way to put a fun and catchy name to their hierarchy of plugins and assets, WooCommerce.com has changed to Woo.com.
So now, plugins like WooCommerce Payments will be more easily referenceable with a shorter name, such as in this case, WooPayments.
This is their effort to standardize and streamline the names of their products and services.
Here is How They Explain It
Woo is how we refer to the brand/company.
WooCommerce is the open-source ecommerce platform for WordPress — Woo’s core product.