Nothing wrong with a little friendly competition as an extra drive though.
Some people have sufficient self-motivation ability already to make large changes to their lifestyle with sheer willpower. More power to them.
But humans are creatures of difficult-to-break habits, and sometimes it pays to find ways to bootstrap or accelerate the creation of new, badass habits to replace the old, squishy whiner ones.
I, and many like-minded others, have found that when engaging in friendly competition, you gain some special habit-changing advantages. For one, a new intrinsic motivator, the drive to win, tips the scales when making decisions, bolsters your willpower, and makes you accountable for your results.
Your new competitors also form a natural group of people to learn from, because they are trying just as hard as you to win at the same game, but have different brains that will come up with ideas you might not have. If the competition is sufficiently friendly, you can even talk strategy with them, but if not, you can still observe and copy what they are doing for a net strength gain! Either way, you're getting several brains and wills working in parallel to optimize each other. They say two heads are better than one, and I happen to think this paradigm scales pretty well.
Furthermore, I've made very good friends out of competitors in many domains, and it makes a lot of sense: We know that we are like-minded and have similar goals, and we know and respect each other in a way you simply can't without going head-to-head.
As for the supposed drawbacks, there are of course going to be people who take it too seriously and become obsessive, but that should be no surprise: things that are great in moderation are often terrible in excess, and like any good thing, competition can be a little addictive. It's something to watch out for, not something to avoid the awesome benefits of competition over!
So I would argue that "making it a race" is exactly what some people need to get off their ass and start running!