This is a popular strategy but IMO one of the worst. While it could work if you're lucky, you lose more when you get donked while takes more spins to break even.
With this strategy, on average, you're risking 5 units just to win back 1 unit. Thus, you need to win at least 6 times in a row just to make a single unit profit.
There are better strategies out there over the poppy 3-2 system.
Back in the day this was one of the first systems I've ever used. Now that I know more about roulette, I'd never recommend this system to anyone new to the game.
It sounds great in theory but is awful in practice, especially if you're playing on a 0/00 which is increasingly becoming the more common table in most casinos today.