No way mobile will be the most appropriate* platform to deal on trade if compare to desktop "in general" even how best it is to the person using it or how smooth and fast the mobile app is.

Mobile are used for certain reasons like, when not a home, when there's no desktop available, even you are in bed or bathroom you can able to trade etc. That's the advantage of using mobile. I too, sometimes used mobile because not all the time Im infront of my desktop but for faster phasing especially at high volume exchanges or when a certain coin is currently on crazy pump, I preferred using desktop.

For being safe, both are safe. It's you generally who will make it safe.