PC More for people who have a lot of spare time and like doing tactics training youth etc but handheld just for fun if you want to have a quick game without having to worry about much other then selecting your team
Also, FMH is cheaper, and therefore simpler in terms of programming and functions in the game, meaning there is less change that you can go wrong; whereas on the PC, you may go wrong on tactics, training, player/manager interaction, finance, etc.
Not really, due to the reasons I have stated above. Since there are less options, there is less you can get wrong. Much like it's easier to get 20/20 than 100/100 in a test, generally.