Is Hikashop integrated with Joomla user profile?

Hi,

If the user go to the checkout and is already logged in, then it doesn't have to login again. However, the customer will still have to enter his billing/shipping address(es).
What you can do is activate the plugin "redirect joomla registration to hikashop" so that during the registration anywhere on your website, it will use HikaShop's. And thus, the address will already be filled when going to the checkout at a later time.