It is kinda expensive, but I can see the folks grabbing them for the simplicity factor. For years I have made my own battery packs for SAR work. Still have a few floating around. Over the years they have progressed from just a battery, to adding outlets for charger to inverters and all. This summer we went on a 6K trip around the US. I had built a camper to tow and really didn't want to install DC. Solution was the Jackery 300. While is cost more than i wanted to spend, in the end the lithium battery, charger, inverter and plugs would have cost about the same and I'd spend 3 weeks trying to stuff it all in a small box to grab. The Jackery could be charged via my old solar panel if needed but most of the time got set in the back seat of the Jeep and plugged into the 12V port to charge while we drove. Simple and effective.
So...I can see folks grabbing the Midland for that reason. Simple and easy to use.