I listen to / watch many podcasts. Due to the data volumes, I download most of them over wi-fi at home so I can consume the content on the go. An SD card is essential for a consumer like me. Even a 16GB phone is quickly overwhelmed when you've got over 80 active podcast subscriptions. I'm "current", so I only have episodes that were released last night and I'm sitting at almost 8GB of space consumed. Considering that my 16GB phone doesn't have 16GB of space, that's over half of the available space.
And more of the video podcasts are trying to go to 4K (why, I don't know --- 720p for a podcast is a good balance between content, video quality, and file size). One of the podcasts I watch released a 2.3GB file the other day (not included in the 8GB above). So, even with phones going to 32GB and more, the content is expanding to consume all of that new space.
So, while YOU may not want an SD card, I certainly do. But I also realize that not everyone uses their phone the same way. That's why there aren't just one model of each manufacturer's phone.