Because SparkPeople factors in an active daily living multiplier which includes some walking, tracking your steps in your calorie fitness tracker may hyper-inflate your calories burn goal which may slow your progress over time. It's OK to use the step tracker feature on your My Fitness Tracker, but it should not be tracked in your cardio tracker as it does not meet the guidelines for cardio (elevating your heart rate between 60-85% of your max heart rate and sustained for at least 20 minutes).
Below is an Ask the Experts response for those members who are on their feet a lot during the day. www.sparkpeople.com/community/ask_the_expe
I hope this helps!