I don't even see how that thing works in the corners. I rock, mud, & tape my own little remodels. I have a Husky bag with trowels, pans, knives, tape, tape measure, and a few other tools... including a hand corner trowel. It works great. LOL
Those angle boxes are great. They can be tough to push. Especially if you use the wrong brand of joint compound. I use USG Plus 3 for most of my work. It pushes through the tools like ball bearings. And it doesn't require much thinning.
You must use a roller and angle head when "stringing tape" in the "angles" with a bazooka because it puts the tape perfectly into the corners. And I mean perfect. So when you second coat the angles with the angle box and head they are perfectly square.
And I have an assortment of knives from 1" to a 4' darby.
Here's a video of somebody using a different brand than I use... same basic principle...
See what I mean about faster?
And I don't tint my mud pink. Must be for demonstration purposes only.

Nobody can do it by hand faster... or better.