When you click on a link to a website in a pdf, it should open the link in safari, where you can leave the tab open, and where you may already be logged into the website the link takes you to. Opening the link in the embeded browser in acrobat means you aren’t logged into anything (cookies aren’t shared with safari), and most of the time you end up needing to copy the link, switch to safari, paste it in, and pick up where you wanted to be in the first place.