Keeping an eye on the progress you achieve through training and dieting isn’t crucial for an individual but it can help. Tracking the progress is excellent for motivation as you can set milestones that are excellent as temporary goals.
A scale can tell you how much of weight you have, but it can’t give you additional data about the nutritional value of the food you eat or the effect of training. If you want to keep track of all relevant data, then you should try the software you can find on this page. It will keep track of weight change as well as a number of calories that you take in.