This reminds me of crypto wallets. I also dispute mike_hearn 's:
> Smartphone HW attestation is better in every way
They're still prone to side-channel attacks like SPECTRE. Crypto wallets are practically immune because they're air-gapped.
[edit] I just realised that's Mike Hearn of early BTC fame. I suppose he would know what a crypto wallet is.
Spectre doesn't work across process boundaries, so I don't think they are. You can't Spectre your way into a banking app on an iPhone. Or if you can I'd like to see it in action.