That's true. Betting once but always in win side is satisfying. However, probably many of us can't do this once per day bet experiment (especially if you are confident with your prediction) due to greed. Because the usual mindset of gamblers are, if you can gain more then maybe you can bet again. Self-control and discipline are really important to avoid becoming a compulsive gambler.
Satisfying as it is but being accurate at all times in a daily basis even for one bet, it's not going to happen in the entire week. I'll wait if someone will actually do an experiment and even for a month doing single bets daily and let's see how it will be on their percentage with the ratio of win/loss rate they will have. Being a sports bettors, we will not be able to control ourselves by doing such thing if during the first week of our bets are mostly losing. It will make us as a compulsive gambler and will have to react on that unless we are already satisfied with how it goes.