Your bitcoin keys will be safer if stored in a Trezor than in your PC or smartphone, for sure. However the risk will still be significant.
Even with Trezor, stealing your bitcoins may still be easier than stealing money from your bank account or credit card, and it will certainly be much safer for the thief. Thus we can be sure that legions of black-hat hackers and criminals will turn their attention to methods of stealing bitcoins from Trezor users.
If there are hidden cameras everywhere, all hardware is NSA hacked and user is not looking at the screen before sending all his money to thief, then the user probably cannot do safe transaction with credit card either.
Don't get me wrong. I think that it is important to talk about these risks and educate users. But if there is nothing what can be done, then engaging in such discussion is useless.
So what can be done that would in your opinion make this safer than your credit card? If I have hacked computer, then thief can steal my money from my bank account. If I have cameras in my appartment, then he might steal from me as well. I have received my computer, credit cards and bank details by post and if NSA or goverment wanted they can block and empty my bank account whenever they wanted.
The added security of this device is that it has to be either bugged or fake or malitious to steal from you and even if it is, then it still needs your computer cooperation, i.e., your computer being hacked, to do it. It is much higher security compared to just storing your keys on your computer. Especially for lumberjack Jack, who never saw linux before.