Yeah your team might get few yellow cards at first when you will use HARD TACKLE but when they will get used to it then no more yellow cards...

And when you will face stronger opponents in say CUP, Champions League semi final and finals then Hard Tackling will come to your rescue...Since if for that particular game you change you tackling to hard then you can end up getting cards and giving free kicks to the opponent...

Analyse the stats you will find that the games your team has not performed well or has under performed you opponents tackles will be generally higher than yours...