The guy lost me at recovery seeds being "paper claims" to private keys. The source code for deriving said private keys from your recovery seeds are out there. You can derive your private keys yourself without the need for any third party support. Also, at least with Trezor, you can import your recovery seeds / private keys into a software wallet such as Multibit, so you're not forced to buy a new one.
Of course you don't need a hardware wallet to store your coins securely. I personally just find it way more convenient to use my cold storage with the ease of a hot wallet.
You do realize MultiBit no longer exists... right?
I did not, thanks for point it out. You can still import from Trezor to (an old version of) Multibit to Electrum... or actually to Electrum directly, apparently [1]. Point being that with the key derivation logic being public there will always be a way to replace your hardware wallet with a software wallet. Of course this also means to stay away from any hardware wallet that isn't open source.
[1]
https://doc.satoshilabs.com/trezor-apps/electrum.html