And Signal avoids FDroid because they don't want someone else signing packages but they can always provide an FDroid repository like many others do and sign everything themselves.
If push comes to shove they'll be fine and pressure to black box signal in the EU is unlikely to hold up if they can just move users to another app store.
Signal’s developers have spoken on a number of occasions about how their aim is to ensure encryption for the masses, not a techie elite.
Mass adoption can continue elsewhere if the EU chooses to go down a route that would make play store support in the EU non-viable.
NOTE: F-Droid does not require app developers to share their keys, instead they build the application themselves and sign it with their keys -- something Signal is not a fan of.
tl;dr their rationale no longer applies.
Either way, this isn't about only offering the application on Google Play or only on F-Droid; but providing the option for both. Non-tech savvy users will always pick the more familiar and easy option on average, Google Play.
> If push comes to shove they'll be fine and pressure to black box signal in the EU is unlikely to hold up if they can just move users to another app store.
Having relatively easy alternatives in place would reduce the leverage the EU has to actually practically enforce this and hopefully pressure them into at minimum non-enforcement and preferably walking back the obviously unenforceable legislation.
But if it looks like they could practically force out Signal and co or force them to adopt this MITM if they want to continue existing, then they might be more likely to pursue it.