It's not essential to count fat grams in order to lose weight (provided you are staying within your Daily Checks Allowance). However if you would like to know you're not having too much fat over a day, you can keep an eye on your fat intake by not having more fat grams than Checks.
For individual foods, if the grams of fat are higher than the Checks, you'll know it's a higher fat food. You do not have to avoid these foods altogether, but if you know something is high in fat, choose lower fat foods to go with it. This balances things out.
Likewise, if you have a higher fat meal, then make your next meal a lower fat choice.