Hi Rolf. This is an awesome breakdown on not only hardware wallets and their value but what the other parts of the entire system mean and how they fit into it all.
I've recently bought my first Trezor and going through the learning curve myself. Sad for a guy who's been buying BTC since 2014. I lost money with the Bitfinex hack though luckily had positions across 3 different exchanges. Really there is no need to take such risks and you've provided an excellent breakdown on it here.
Best
Chris