So .....there's not that much to it??
When searching for a "why", sounds like the answer comes down to a, "why not?"
And true enough , she's got to sing something. I WILL SURVIVE sends them on their way to the exists just fine... so ya, why not ...

It's easy for her to sing , its easy for the crowd to sing, its familiar, its uplifting. And for thirty years its the only song Ross can up with that checks off those boxes....
Won't use the word "lazy" for it, I'll stick with "easy" ......