Juggluco is obviously developed by someone who hates the portrait only mode of Librelink. If you want that glucose curve to be displayed with 6 hours in one centimetre, you should use Librelink or so. It is meant get a better picture of glucose values than is possible with Librelink, Freestyle reader or Libreview which are all the same concept. For the same reason the screen is not taken up with a menubar or icons. The content of the menu you can see by pressing a certain part of the screen, which also doesn't use the terribly slow material design animated menu of android.
But in Librelink I was not even able to decipher the glucose value before the meal the previous day.
"Invert screen" and "disable camera key" seems a bit superfluous, but scanning is on one side of the phone, which makes that you touch the phone in a certain manner which can influence how you touch the screen during scanning.
I have no experience with other apps displaying glucose values coming via Bluetooth from Freestyle Libre 2 sensors.