Officially, she chose it because her new music isn't quite ready yet,,- but it wouldn't surprise me if Marion Kraft, her manager, didn't also recommend it, as a way of reminding radio, and the industry of her relevance ("The Weight of These Wings", and the Pistol Annies project are labours of love - but they push her further into the Alternative/Americana sector, and don't really gel well with radio's agenda).
The songs she's chosen for the medley, though, seem to be “Kerosene,” “Gunpowder and Lead,” “Mama’s Broken Heart, “White Liar” and “Little Red Wagon”, which reached 15, 7, 2, 2, and 16 on Billboard Airplay (thereby missing out all three of her number ones). The reasons she gives is that they represent milestones in 14 years of struggle, and that "People have to remember a hit isn’t a position on a chart, it’s what people sing along to.” So I think her approach to it is still personal and tather unorthodox.
There will be less than a minute for part of each song - I'm afraid I'm not usually keen on medleys of this type - I was one of the few, it seems, who wasn't too keen on the one Carrie performed at the end of the "Blown Away" era, and I'm not greatly looking forward to this one.
Miranda, though, still seems to be showing a streak of satirical fun about the whole process. She posted a spoof medley on Twitter, consisting of clips from the "Glam Jams" she records backstage. The regulars in these are her hairdresser, Johnny Lavoy, her dress designer, Tiffany Gifford, and her make-up artist Moanie Lee, often with her backing singer Gwen Sebastian, Blu Sanders , a singer and writer who sometimes acts her crew chief on tour, and other friends from time to time.
https://twitter.com/mirandalambert/status/1114615062822621188
Meanwhile the promise of new music seems real - she's mentioned June this year as the first song release. Of the new music she says “I’m happy and I’m healthy, and I’m ready to kick ass again. I feel like I’m taking some risks and not being afraid. I’m going into fearless mode musically and heart wise. I feel like they go hand-in-hand. I’m jumping out there and taking risks, and I feel good about it. I’m going in and we’re making it, and we’re putting it out as fast as we can.”
https://eu.tennessean.com/story/ent...lambert-tour-new-music-acm-awards/3391154002/