Might not apply to most people, but on some of my machines I have left the mail app unconfigured and so the few times something uses a mail link launching the app will just land me on the setup screen. It’s rare enough that anyone uses those sort of mailto: links that I haven’t bothered doing anything about it. And it might be that most other people have their email program set up already so only me and a handful of others run into any sort of issue with that :p
funny you say that, you are the first to mention it but I personally use Gmail installed as an app from my browser, so I encounter this exact issue hahah. Even worse, there was a time where I uninstalled outlook completely. It was also pretty messy in that instance
I kind of assumed that if someone found themselves in that position they would contact me another way and it shouldn't be a dealbreaker haha