all very valid points, totally agree with what you said.

Just a side note and illustrative example on the issue of phone storage space vs SD card space:

Just in the past week or so in the U.S., Amazon changed their Amazon Prime member's video streaming service to allow the free download of movie and TV show files to their apps on Android and IOS devices. Meaning, you could watch downloaded TV and movie shows like on an airplane trip on your mobile device, when you might not have internet access. That's great, I thought, and set it up on my Android devices today.

Turns out, the Amazon Android app apparently defaults to automatically downloading any of those files ONLY to your Android device's ROM space, and doesn't give you any options for changing those downloads to your SD card space. So, I have a couple of older devices with limited space, and when I went to try to download a movie file, the app popped up a message -- Insufficient disk space to download the file.

So, just to illustrate, there are times when you need/want more space on your device's ROM, and having a big-size SD card just isn't a workable substitute.

Google Play Music used to be the same way, in that when you streamed music from Play Music, it would cache the files on your phone's ROM and you didn't have the choice of relocating those files to SD card space. Unknowingly, I one time streamed a bunch of albums and suddenly found that all the available ROM space on my Android device had been eaten up. Fortunately, AFAIK, the more recent versions of Google Play Music (I think for Kitkat and above) now allow those files to go to SD card space.