Hi @dovroc,
Thanks!
All of the buttons on the non-checkout pages like single-product page, cart, or mini-cart will initiate the express checkout and redirect the user to your native WooCommerce checkout which is then already populated with the address details from the PayPal account.
https://woocommerce.com/document/woocommerce-paypal-payments/#section-12
There is no express checkout button on the actual checkout page for now though.
The smart button on the checkout page works a bit differently and requires the user to first input their details into the WooCommerce checkout fields.
Though there is currently a small problem with the checkout validation, allowing users to click the smart button even before inputting any details, which will be improved in the next update. The button on the checkout page is not supposed to transmit any address details from PayPal to WooCommerce.
We have a feature request in our backlog about an express button on the checkout page, but currently, no concrete plans to implement it.
Kind regards,
Niklas