From your link I read and understand that Cold wallet is basically called hardware wallet. Where it is offline. It is like a device. Which is much more secure. I understood this much. If there is no internet then how do bitcoin transactions take place?
Since this is more secure then do those who hold a lot of bitcoin use it?
If you keep bitcoin in a normal wallet then how can this wallet be hacked? As far as I know, bitcoin wallets cannot be hacked.
You are complicating the meaning of cold storage.
A cold storage isn't just about device, it means your private keys are completely offline and never touches the internet. Examples are hardware wallet, airgap wallet, and paper wallet, the three keep your keys offline and don't have any touch with the internet.
Hardware examples are Trezor and Legder, to use them you have to connect the device to the internet to be able to use them but your keys are safe from the internet, the connection can be established with a USB type c cable and Bluetooth where as;
An airgap device doesn't make any connection with the internet before you can use them, the device doesn't have any connection with the internet, once internet is established, that wallet isn't longer an airgap wallet. Most often, the connection are done with a QR code and SD card. Some airgap wallet comes with camera for scanning a QR code of psbt transaction from online wallet to the offline wallet to sign the transaction and then scan with the online wallet to be broadcasted on the Bitcoin network while some are sd card built for transfer of psbt from an online wallet to the offline wallet to be sign and broadcasted for confirmation.
Paper wallet is also a cold storage where your keys are generated and printed on a pieces of paper, it's only when you import the wallet online it no longer a cold storage.
