I have not owned a scale in my life. Used to use the one at the gym or the one at my parents or the one at the department store. Now, I am thinking of getting one.
A few weeks ago I stepped on my sister-in-law's scale and it showed a larger number than I had ever seen: even though I am certainly down quite a bit over the past 9 months. This got me thinking that maybe I should drop the cash and get a bathroom scale. A year or so ago I may have had as hard a time buying a scale as buying an off the rack suit.
Or, I could save the money from the scale and get a larger set of tires for my xmas present to myself: a Specialized Roubaix Expert. dunno.
Both can be useful tools to measure progress, or at least remind you of where your are.
Both can also be 'buzz-kills' if they cause you to lose focus.
Neither one will do the work for you, but both can help you as you work towards whatever goal you set for yourself.