The problem is probably a legality thing. In Germany for example AFAIK people need to be told they are recorded and must accept to this. So by implementing such a feature, you need to adhere to local laws, which differ from country to country and may make it way to complex and dangerous to implement.

I just downloaded it yesterday from F-Droid yeah. It's in the Izzy repo.

Android's Messages, Dialer apps quietly sent text, call info to Google

Google's Messages and Dialer apps for Android devices have been collecting and sending data to Google without specific notice and consent, and without offering the opportunity to opt-out, potentially in violation of Europe's data protection law.

According to a research paper, "What Data Do The Google Dialer and Messages Apps On Android Send to Google?" [PDF], by Trinity College Dublin computer science professor Douglas Leith, Google Messages (for text messaging) and Google Dialer (for phone calls) have been sending data about user communications to the Google Play Services Clearcut logger service and to Google's Firebase Analytics service.

"The data sent by Google Messages includes a hash of the message text, allowing linking of sender and receiver in a message exchange," the paper says. "The data sent by Google Dialer includes the call time and duration, again allowing linking of the two handsets engaged in a phone call. Phone numbers are also sent to Google."

The timing and duration of other user interactions with these apps has also been transmitted to Google. And Google offers no way to opt-out of this data collection.

The default app is only just like any other app. The fact that it is the default / preinstalled doesn't mean it is minimal or necessary software. In fact any company can release their own slightly modified version of Android. That's also the reason why a Samsung smartphone, a google pixel and some other random small company might all have Android xyz installed but you get a different set of preinstalled apps, different Launcher / home screen or standard settings.

So what your default app does or can do depends what or whose app it actually is and random people from the internet cannot tell you more about it if you don't give more context.

Wait, you guys get phone calls?

Tbh I like that. That way no one but me can answer calls on my phone.

They also released a Fossify messenger and contacts app. You might have to enable or refresh the IzzyOnDroid repo to see them now, or wait until they come to the default F-Droid repo.

One option is QKSMS

Another is Connect You

Fossify Messages (fork of Simple SMS Messenger) should be released on F-Droid sometime soon.

I just clicked each link and installed them