A set of bathroom scales can be a good measure of progress, and a form of inspiration for some people. And a massive source of problems (such as stress and guilt) for others. I think if you find them helpful then use them, and if they make everything seem harder, forget about them.
I like to use them, but then there are some other types of measurements that I don't like to use. For example, when I used to go jogging I would rarely time myself, as I found that to be annoying and detract from the enjoyment of it — and I'd be less likely to go at all.