Is point 2) still valid nowadays? I know many years ago ssd durability (when unpowered) was low, but hasn’t that significantly improved to the point of not mattering?

And what’s the alternative you’re proposing, spinning rust? Is that what you yourself are using, is all your non-system data on spinning drives? Imo better would be “store all your data on quality ssds if you can afford it, and do 3:2:1 backup for whatever you can’t afford to lose”.

Just one piece of anecdata - I have a nas at home with 5x16tb seagate spinning drives, and a consumer grade 8tb sata qlc Samsung ssd in the sixth slot. One of the spinny drives completely died after few months and needed replacement. And the consumer-grade samsung ssd still going fine after 1.5 years of power on hours with a small but continuous write workload.