Well there are many who don't want to pay for a hardware wallet so this only helps them. TBH both of them are but in case of smartphone it is heavier since we carry it all the time and chances of getting stolen are pretty likely. In case of hardware wallets, there are vulnerabilities which if is not found before someone who have malicious intent then it could lead to higher damage. Well most of the times it gets fixed on time but still risk is there.