The risks also exist on computers or laptops but I thought the risks on mobile phones/ devices are higher. It comes from total online time people spent on mobile devices likely higher. It means they expose their wallets with more risks.
Incorrect. If one backup wallet seeds/ private key, then even they lose their mobile phones, they won't lose their money only if they response fastly because the others can crack wallets' PIN/ passphrase to steal their money. Reponse fastly mean accessing the wallet on other devices and move their funds in that wallet to the others ASAP. If you lose your phones, I think you have enough time to secure your fund but you have to do this quickly. Because the odds to have the one who takes/ steal your phones have enough technical skills to hack your wallet's PIN/ passphrase immediately by his/herself is very low. There are not high coincidence like that.