Tough crowd! That's what we used to do, but some extremely vocal people weren't satisfied, so we've done this to integrate our intentions into the license itself.
> Provided that you are otherwise in compliance with the GPLv3... [we] also grants you the additional permission to convey through the Apple App Store non-source executable versions of the Program as incorporated into each applicable covered work as Executable Versions only under the Mozilla Public License version 2.0
1. The phrase "only under the [MPL]" definitely means my app store binary isn't distributed under the GPL
2. The phrase "Provided that you are otherwise in compliance with the GPLv3" does not seem to have any effect for distributing "only under the MPL". By distributing software "only under the MPL", I do not "otherwise" have GPLv3 obligations for me to not be "in compliance with".
3. Unless you intend to say that I have both GPLv3 and MPL obligations, in which case the same GPL obligations which [allegedly] prevented me from using this in the app store are still in effect. Also, this would contradict 1.
Please have a lawyer look at this. I guarantee my clients' legal counsel would not allow use of a library under these terms.
OK, I'll admit that this is in fact clearer than the Mosh approach. (My main confusion was whether you expected me to offer source if the only binary I distributed was an iOS app; the Mosh waiver is very clear about that.)
Yes, the expectation is that you still have to comply with the GPLv3 (including making the corresponding source for your derivative work available), at which point you have the additional freedom to distribute the app through the app store.