Am I really understanding how the "Trezor Model T", and hardware wallets in general, work?

Question

Getting increasingly paranoid about losing my coins, I've yet again (for probably the 20th time by now) went looking for hardware wallets. The only semi-reasonable one seems to be the two Trezors. All the others seem fishy/unreliable to me.

But as I read and watch and listen, it seems like even the "premium" Trezor Model T requires "OS support" and even to go to a webpage (not hosted on the device itself) to actually use it. Its operations are not at all self-contained in the device itself.

Up until now, I always had the idea that the Trezors (even the first model) is entirely self-contained, and only plugs into a computer in order to use its network capabilities to be able to send coins and update its data. (Of course, doing all the validations and verifications on the device, so it doesn't have to trust the network or the computer it's plugged in to.)

Actually, I vaguely had the idea that I would be able to buy one and then physically take it with me somewhere, without any computer around, and sort of "beam" any amount of my coins into another person's Trezor or even other hardware wallet...

None of this seems to be the case. Even the expensive model with the touch screen appears to be entirely reliant on the "host computer" to do anything besides storing the coins. I bet the special Trezor "coin control panel" webpage doesn't even support my browser (I don't run spyware), and who knows how long that will stay online? I don't want to rely on some company's website, or require special "OS support" for my hardware wallet. That's why it's a hardware wallet! For it to be stand-alone.

Am I missing something fundamental? Are there no "actual" hardware Bitcoin wallets which can do everything by themselves: send and receive coins without any computer? I don't even have wireless Internet at home, but most people apparently have, so I definitely expected it to be using "wifi" on its own, but this doesn't seem to be the case?!

I really tried to find this out by myself before asking.

Answer 1

Hardware wallets such as the Trezor ones you mentioned are only a secure method of storing and using your private keys. When you want to send BTC, that transaction will be signed mathematically completely within the confines of the key itself.

One could design a hardware wallet with a full user interface, negating the need for a separate computer all together, but that would be far more expensive; in the realm of the price of a modern mobile phone. Keeping the code inside a Trezor to the utter minimum reduces the potential for security weaknesses and improves reliability, too.

Answer 2

Note that hardware wallets do you store any bitcoins. Without going too technical, hardware wallets securely store the private keys (derived from the special 12/18/24 words). All your bitcoins are stored in the actual blockchain. You use your private keys to unlock your funds in the blockchain. Think of your wallet as the key and the blockchain as the vault. The hardware wallet does the necessary cryptographic calculations to query your funds or send bitcoin to another address. It cannot do it offline, it must require internet connection to communicate with the blockchain.

Actually, I vaguely had the idea that I would be able to buy one and then physically take it with me somewhere, without any computer around, and sort of "beam" any amount of my coins into another person's Trezor or even other hardware wallet...

That is technically possible but that means the wallets will require some sort of NFC and also connection to the internet (4G/5G/WiFi). The wallet will also require better CPU and higher RAM. This will significantly increase the price of the hardware wallet and also make it bulkier.

And finally, no, you do not necessarily need to use the Trezor website. You can host the web interface right on your laptop but might be of an overkill for any average user. See https://wiki.trezor.io/User_manual:Running_a_local_instance_of_Trezor_Wallet_backend_(Blockbook)