Earlier quoted context omitted.
I really hope not. I'm not saying localization isn't important, but holding back an English app because of this is something I don't understand. A huge part of the world speaks English just fine. Release first, localize later if it's not possible right away. This is probably not the case here, but I hate it when devs forget that the US isn't the entire world that they're releasing their app to.
Also some of us don't even like to have the software localized. English is not my mother tongue and it's not an official language where I live either but I always set the system language to American English on my computers and devices.
I do however prefer a German locale as in number, time, units, etc.