I don't agree with the parent post (I think all traffic should be encrypted now that let's encrypt exists) but this is an interesting point.
For example, Google is making it as difficult as possible to install certificate authorities in Android.
Root certificates are encrypted as if they are client certificates, requiring the user to set up PIN or password protection on their lock screens. Removing this protection immediately disables the installed user certificates.
Google has changed the Android 7 API so that by default the user certificate store is not used to validate the validity of certificates (only the system store is used). Apps need to opt in to still support user certificates.
Of course this is all done to prevent malicious actors from performing MitM attacks on users. Still, I would not be surprised if Android P removes the user certificate store all together.