Made my morning as well! I was briefly annoyed at the money spent on the Binax tests, but now I'm looking at is as an acceptable tax on being able to worry less about getting home. Whether or not this is wise from the standpoint of containing spread in the U.S. is a topic for another discussion.
That said, and speaking only for myself, if anything, masking is going to be more important. Many travelers are going to be less cautious, knowing the pre-return test isn't hanging over them. Even otherwise very responsible people, who'll continue to mask in museums, on trains, and planes, etc., will inevitably slip up more often. I'm counting myself as likely to be in this category. We're all human.
Also, for those of us on RS tours, or any kind of similar plans, it's going to be no less important to avoid infection--unless that has changed too? I actually almost missed the announcement (a friend texted me about it) because I've been, ironically, busily prepping my tech for travel.
Caroline