I had an issue where a client reported a crash on login. The exception and stack trace reported were very generic and lent no clues to the cause. I tried debugging but could not reproduce. I eventually figured out that the crash only happened for release (non-debug) builds that were obfuscated. I couldn’t find the troublesome code, so I figured out which release introduced the issue, then which commit, then went change by change until I was able to find the cause. It turned out to be a log message in a location that was completely unrelated to login. That exact log message was fine a few lines up. Other code worked fine in that location. For some unknown reason, having that log message in that specific location caused a crash in a completely different area of code.
I’m from the US as well, and I can verify that very few average people use those types of messengers primarily. It is almost exclusively iMessage and SMS/MMS/RCS texts as the main form of messaging. I will admit that quite a few people will use the messaging features that are built into social media apps (like messaging in Snapchat, Facebook Messenger, etc). At least to me, it seems like those are moreso used for sending memes or messaging people you don’t interact with regularly and are still secondary to the other forms of messaging.