Obviously right now it has, but we're comparing a 3 hour old song to a 3 day old one. If Gaga couldn't overcome Roar at this point then it'd be an embarrassment for her.
Give it a couple of days and then we'll see if one has overshadowed the other or not.
For stans, it might not make a difference. But for the General Public, who are supposed to be enjoying new Katy on the radio, Applause is just punchy, loud, and different enough to give "Roar" the TKO that will make people forget it exists