I usually recommend hardware wallet when the person is aiming to hold a significant amount of money in his portfolio so as to optimize his security for better user experience with limited chances of getting scammed. But if his intentions for the time being is a hold a small amount of coin then mobile wallet is the best option for him, and for optimum security he can choose to make use of a separate device which should be an airgapped device for the purpose of his Bitcoin wallet only. It's more cheaper than buying a hardware wallet and more secure than using your regular mobile phones.
Yes I think i understand your point but what amount is considered to be small to you someone investing something around $500 below can still store its coins on hot wallets and with proper back up and protective measures it would still be safe but does that makes it the best option, I would say No, cold wallet is still the best option regardless of the amount because hackers do not necessarily care about amount most of the time. Airgapped device for cold wallet is a better storage option not to only mobile device wallet but to even hardware wallets if setup properly. But it is not sometimes cheaper than some Hardware wallets.
Also it should be worth mentioning that it is not just any abandoned device that can be turned or regarded as an airgapped device, it must be confirmed that it has never been online before, because only then do you eliminate all traces of drawbacks