It maybe important. but If you are a amateur player, if you start calling footfaults, no one will want to play with you and same will happen in doubles play too. and soon no one will want you on their league or team play.
Now, this is change if you get to national championships and so on but til then, don't call footfaults.
Babolat Pure drive 2012, 55 lbs, Kirschbaum Proline X / X-1 biphase. Nalbandian backhand and Nadal forehand.