I haven't day traded for hours in a long time but still I make use of my laptop anytime I want to trade, laptop makes your analysis limitless. The views from the chart would be bolder and clearer. The mobile screem is small compared to that of your desktop or laptop so they'll be more preferable options.
My Mobile could be used to just stay updated with the market using my app that's if I need to do some other stuffs that'll involved me leaving my desktop for some seconds.
Secondly for the security reasons I'll still have to go with my laptop as my mobile is used to access more unsecured sites compared to my laptops. For example my social medias platforms, gaming platforms etc are all access with my mobile so just to stay security cautious with addition to other benefit of using a larger scream, my laptop has to be my go to option.
I have to say even desktop PC could be better. Think about it, if you have 8 monitors, all looking at some other chart showing you what's going on at the same time and you have your last monitor right in front of you looking at the exchange, just waiting for you to click buy or sell based on what you are seeing on the other monitors? That's the thing about desktop computers, they are the real limitless ones, mobile is definitely worse than a laptop, but a desktop has so much more room to grow, it could grow bigger than you can ever imagine, you can plug it into a HUUGE tv as well and look at it there, just divide the screen into 8 different things because if your screen is big enough you do not need other monitors.
In that case desktop is by far the best one, if you want hours and hours of trading, laptop is not easy because it Is still quite small to check everything, bigger than a phone, but still not enough if you ask me.