Chances of your second phone with mobile wallet app being stolen, lost, broken, becomes suddenly a brick after a new firmware update is higher than simply holding funds on a ledger/trezor like hardware wallet.
There is always a chance that something bad happens, but there is something called a backup that works on the same principle for any type of wallet. When something is stolen or broken, we use backup to recover lost information. The only difference with what is stolen is how good the protection of a particular device is, or rather to say how long it will take a thief to hack protection and steal assets.
Plus this hardware wallets have built in security, and your mobile has? Pin code ? Home screen protection code ? 
I wouldn't agree that the thing is so simple, it actually depends on the device itself - whether it's a smartphone or a hardware wallet. Security in for example Trezor HW is somehow compromised because there is an unrecoverable exploit that allows a thief to retrieve a seed in a very simple and fast way if the user has not set a passphrase.
Looking at the average smartphone, these newer ones have a fingerprint reader, PIN and face locking, but I think every mobile wallet is had PIN lock (at least Electrum is have), and you can encrypt your data as additional protection. Which would be easier to hack in a specific case, Trezor HW or smartphone locked with PIN/fingerprint + extra pin for crypto wallet+data encryption?
The only thing i do not agree with is anti malware, either for your mobile phone, or your laptop, you do not need anything called anti malware.
For your phone and pc, all you have to do is activate the windows malware defender thats inbuilt with the devices, then you are safe.
For your phone and pc, all you have to do is activate the windows malware defender thats inbuilt with the devices, then you are safe.
It is never wise to underestimate the enemy, in this case malware, spyware or adware - and I personally have great confidence in Malwarebytes Premuim protection who has been serving me very well for years. What is a problem for most of those who do not want to use commercial av/antimalware programs is their cost and the old myth that they use too much resources and slow down their computers. But on devices that have sufficient RAM, this impact is almost negligible.