change case sensitive HDD (APFS) to non case sensitive

My guess is curiosity. And a lack of understanding that its only real benefit is for SSDs. That's my take anyway.

I am having some difficulty understanding exactly why case sensitive is 'good'

I dont see an answer to the question in there.

In simple terms betas are unfinished, if your work is best done with unfinished software go ahead, it is your work after all.

Amazing. I've been using Macs for a couple decades and have never run into a problem. I guess it only affects a few.

I just gave an example of an extreme case where I did get APFS+Case Sensitive without my explicitly asking for it. The beta worked as intended - case sensitive is *good*. The issue here is Steam and Adobe, and the challenge to get our file systems back into an inferior format just for the sake of running those apps.

"When you install macOS High Sierra on the Mac volume of a solid-state drive (SSD) or other all-flash storage device, that volume is automatically converted to APFS." <-- not just on install though.

But indeed a mechanical HDD it's better to keep as HFS+ for now - "it it ain't broken, don't fix it", specially if you need the disk for time machine (albeit I have my time machines on dedicated sparse bundles, so the underlying filesystem is a bit irrelevant).

All my systems are SSD nowadays. With 1TB SSD at about €300, even my old Mac mini got upgraded. Hence why I "suspect" that the conversion from HFS to APFS+Case sensitive only happened "in certain beta cases" and only when encryption was enabled, as only my laptop has encryption enabled.