You don't have to launch it when you're not playing Splinter Cell.
The thing that bugs me most about Origin and Uplay are their less streamlined backup process. I have no complaints regarding their functions for actually downloading and playing games.
As to the game itself, I really enjoyed it back in the day, but I'm not as familiar with other popular stealth franchises like MGS or Assassin's Creed. It was a good first installment, but I think the series really started to shine at Chaos Theory.