This is the best advice you're going to get.
Another reason why hardware wallets are secure is because the bitcoin is secured "on the hardware". Technically it's on the blockchain, but the access is through the hardware. Without the hardware you can't access the blockchain to get your bitcoin.
I get your point. So it all goes down to your seed. As long as no one knows your seed, you are safe no matter if you use mobile or hardware wallet.
Definitely. As long as your seed is safe then you're fine. But then again, mobile phones are significantly more vulnerable compared to hardware wallets in terms of your recovery seed getting stolen.