Only under certain conditions . . .
which cannot be discussed on a public board.
If you're really interested in this game, and are willing to devote a lot of time to learning the dozens of different plays, surrender indices, etc., and seek out specific conditions that may not be obvious at first, the game is very playable.
I don't recommend SF21 for the Las Vegas visitor or other part-timers, though. The time spent learning SF21 and locating good conditons would most likely be better spent on "normal" games.
Be assured that it takes a lot of learning and effort, the discipline to absolutely NOT PLAY under other than excellent game conditons, and a very large (for single deck) bet spread to make money at SF21.