Setting aside this last page with its bickering, an interesting discussion.
I had a SS S0. I replaced it with an Al S3 as that was all I could get in NZ after LTE became a thing. While owning the S0 I became a wheelchair user, and the Ion-X glass of the S3 picked up weird scratches around the edges that I couldn’t get rid of. They came from the aluminium door of the office I was working in at the time as it would catch my watch sometimes as I pushed through it. The S0 didn’t have those though I used it for equally long as a wheelchair user using that door.
My Al S4 wasn’t so bad as I changed jobs and didn’t have that door to contend with by the time I got it, but it still picked up marks around the bottom edge from hitting stuff I couldn’t avoid. My wife’s S4 Al also has a similar mark on the corner of the glass.
Now that we can get SS here that’s what I have.
I have no case and bought AppleCare+ on my iPhone 11 Pro Max (and my MacBook Pro, but I’ve never had one since 2012 that hasn’t broken and needed a major repair, which is why I buy it for them), but when I sell that in September it will add value to a phone that will still have decent residual value as well as providing an affordable replacement if I drop it and break it. For the watch, assuming you want LTE, the price here is NZ$380 more for SS. AppleCare+ is $169, and if you need to use it you pay $119. That’s $288 to replace a scratched Ion-X watch, and $407 to replace it twice.
I’m not suggesting I’m right and anyone who disagrees is wrong, but personally I’d rather pay $380 more up front and have a watch that I think looks nicer and won’t get scratched, so I don’t need to deal with the hassle (we have no physical Apple Stores, so it’s a send it off deal for service).
Yes, I could smash it completely, but my home contents insurance would cover that for a $300 excess, as they did when I dropped my phone onto my iPad Pro and broke the screen. I had a new iPad with full new warranty the next day for $12 more than AppleCare+ and the replacement of a watch would cost. I’d also get a new charger, charging puck and band.
TL;DR I have personal experience of Ion-X being marked in a way that sapphire does not, and unless you want a GPS only watch I don’t think the extra cost for SS is excessive if you’re also going to buy AppleCare+ in case you scratch your Ion-X.