Having very little time to play poker while still enjoying the game - spins are my go to choice on a regular basis, unless I have a free day when I might sign up for tournaments.
To be profitable on spins, depending on the stakes you choose to play, you should have at least 45-48% winrate over thousands of games, which isn't an easy thing to do if you don't know the fundamentals and you are not analyzing your games and your opponents "meta" via Pokertracker for example.
Also, different times of the day can be a factor for your winrate, when you can get matched against weaker opponents, but that's not really a way to improve your game.