Actually it's the same as trading on a cellphone or PC, but only one thing that makes me feel uncomfortable when trading via cellphone is that I will find it difficult when I will look for other information and for me cellphones will be more comfortable when we can't be in front of a PC or laptop.
It's very to difficult to use a mobile phone in trading because there is some feature that you can't view in mobile phone and I think a mobile phone app exchange site is prone to hacking. I strongly recommend as a trader to use laptop/PC for the convenient transactions and other activity in trading. You can still used a mobile phone in monitoring the price value on the market which also comfortable if where you are because it is handy.