Yep! A step is a step is a step!
The way to use the ped is to wear it for a week, keeping track of your daily step count. At the end of 7 days add up all of your steps and divide by 7 to get your daily average. This is your natural baseline and all of those steps really count for 0, cos they are what you have been doing to gain your weight (if you see what I mean).
Assuming you are aiming for the magic 10,000 steps to get the health and weight loss benefits, you simply add 10% every week or so until you reach the magic number. Take it easy, don't rush it and enjoy!
The other factors to remember are intensity of movement, leg speed and arm movement. When you walk you may just mooch around at window shopping speed. Walking Away the Pounds you might take things up a bit because you are deliberately trying to exercise!
I hope that helps