It will never be centralized.

even if they are the safest way, i would not suggest to use them as a "main" wallet. Keep in mind a smartphone is a daily use gadget. what if you drop it on the street or you get robbed by a thief on the streets and so on. nono no matter if android or ios device.

Of course its not 100% sure. But the hacker needs physical access to your hw wallet, what makes it harder for the hacker. (Or he manipulated the hw wallet before he sold this to random people).

Still the safest way to safe coins. just my 2 cents.

The money controls it....