Britney Spears fans are rejoicing at her return to the stage. Spears recently kicked off her two-year residency at Las Vegas' Planet Hollywood Resort & Casino with the opening night of "Britney: Piece of Me," and predictably, the show is already receiving rave reviews.

After claiming that all music would be performed live, however, Spears has been called out for lip syncing. According to the Daily Beast, Planet Hollywood has admitted that Spears sings along to a backing track throughout her show, and several spectators have expressed disappointment with her lip-syncing.

But really, who cares? It's a little surprising that one would expect Spears to live sing every note of her "Piece of Me" show in the first place. Maybe it's for the best that she's taking advantage of the backing track for these performances. Here are five very good reasons that it's totally fine for Britney to make use of technology and lip-sync a little during her Vegas performances.

1. She's dancing her butt off out there

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Britney's complex and fast-paced dance moves are labor intensive. Who could possibly hold a pitch while writhing all over, lying on their back, or jumping up and down? Spears is well known for her exciting and high-intensity dance performances, but she'd be gasping for air if she had to sing at the same time.

2. Check out her costumes



She's really supposed to sing in a winged corset and harness while she's flying? Costumes are a huge part of Britney's performances, and that includes the girdles, wireless microphone equipment, and stiff materials that come with them. Her costumes are made to dazzle and awe, but that doesn't mean they're particularly comfortable for singing or conducive to expanding her diaphragm.

3. Music is only one part of the show



Fans don't go to a Britney Spears concert to hear her pipes; they want to see her music turned into a spectacle. Younger followers care less about voice and more about performance, and that's okay. If fans love the recorded versions of Britney's music, then the backing tracks aren't taking anything away from the performance. They're opening the door for the crazy showmanship people want to see.

4. She's hedging her bets



Spears' latest album, "Britney Jean," showed lackluster sales and her "I Am Britney Jean" documentary was a flop, so she's going with what she knows works for her -- flash, glitz, and glam. From that '90s fedora to to the "Toxic"-era glittering bodysuit, this show is the definition of classic Britney.

5. This is Vegas, people



Expecting to hear Britney's live voice throughout an entire performance of this complexity is sort of like expecting all of Vegas' burlesque dancers to boast au naturel breasts. Knowing that something's not 100 percent real doesn't have to make it any less magical.

So as a wise actor once said, leave Britney alone. Let her lip sync. She knows how to put on a performance, so sit back and be entertained.