I can't understand one thing only. How could hardware wallets be compared to mobile ones?
We always consider certain characteristics for each wallet, being open source versus closed source, custodial or not, cold/semi cold/hot wallet,...
A hardware wallet could be considered a semi cold storage and most of their software is open source and the keys are both generated and kept in your device.
A mobile wallet depending on the software you are using can be anything so lets be specific and use Electrum. It is 100% open source, keys are both generated and kept locally but it is hot storage since a mobile device can not be cut off from the different types of networks ever. Also you always carry your phone around with you so you shouldn't store all your bitcoins in it ever.
Security-wise a hardware wallet can be safer than a mobile wallet.