K seriously, wtf is up with this phase?

"I Will Be"- composed by Avril Lavigne.

Avril's take:

Leona Lewis' take:
("Hello, I'm a diva skank")

"Taking Chances"- composed by Platinum Weird

Platinum Weird's take:

Celine Dion's newest "single":

In regards to the above, I love how emotional and raw Avril's version is; there is something about the way she sings the first "All my life" that sounds incredibly sad to me.
But Leona's is pure and simple "showing off m'voice to m'homiez." Uck.
And I actually think Kara DioGuardi outsings Celine Dion in the 2nd one. Celine almost sounds in pain.

So what's up with this new trend? Why's it happening?