It's in an offline wallet, right? And backed-up somehow incase the hardware wallet dies. And that backup made with an known-clean, freshly-installed, offline computer to avoid malware stealing it when you're making the backup.

Nope, but it's still more secure than an exchange

I expect to lose more from btc's value crashing than some elite conspiracy of hackers having sabotaged my hardware & somehow working out my private key which isn't stored in plaintext

If I was holding a really great worth of btc, going the full mile of cold storage would make sense. At that point you're invested, quit kidding around

But you had to know to do that.

Semi-related, it’s wild to me that the best practice for a digital currency is the functional equivalent of keeping your money in your mattress.

I used to be a supporter of bitcoin but then I gave it some long thought and realized bitcoin will never make it as intended. The very essence that makes bitcoin appealing is what keeps it from being user friendly and functioning safely. Once you try to fudge with that, you undermine everything bitcoin is supposed to address. There is just no way around it.