Halsey's Arena Tour

This is Halsey. (It sounds cooler if you say it like "This is Jeopardy.")

You may know her as the female lead in The Chainsmokers' 2016 #1 song, Closer. You may also know her from her current solo song, Now or Never which reached #17 on the Billboard Hot 100. While I try to keep up with popular music, I'll admit that this is all that I know about Halsey. However, I recently heard commercials that she is coming to Washington's Verizon Center in October as part of an arena tour.

While it's possible (likely) that I'm out of touch, how is Halsey big enough to do an arena tour? Yes, she has 5 million Twitter followers and had the #1 album in the US (according to Wikipedia, "Hopeless Fountain Kingdom debuted at number one on the US Billboard 200 with 106,000 album-equivalent units, of which 76,000 were pure album sales"), but here are bands/performers that have played or will play at Verizon Center in 2017.

Jay-Z
Janet Jackson
Green Day
John Mayer
Red Hot Chili Peppers
Chris Brown (and others)
The Weeknd
Eric Church
New Kids on the Block with Paula Abdul and Boyz II Men
Kendrick Lamar
Daryl Hall and John Oates and Tears for Fears
Queen + Adam Lambert
Roger Waters
J. Cole
Earth Wind & Fire an CHIC featuring Nile Rodgers
Shawn Mendes
Depeche Mode
Arcade Fire
Ed Sheeran
Katy Perry
Bruno Mars
Tim McGraw and Faith Hill
Enrique Iglesias and Pitbull
Guns N' Roses
Imagine Dragons
Lady Gaga
Andrea Bocelli

There are plenty of superstars listed in this group. While there are others where you can debate whether or not they can fill an arena, it seems like all of them have more impressive resumes than Halsey. Again, I may (and probably am) out of touch, but my question still stands: how is Halsey big enough right now to do an arena tour?