Rainbow Six: Siege is so exciting you will want to watch it from every possible angle, says Ubisoft.
The latest Rainbow Six: Siege developer diary covers a lot of ground, but one of the main themes is that the tactical action really is a hardcore team game. Because it's played in co-ordinated assaults (well, assuming you intend to give your opponents any challenge at all) it makes for pretty compelling action.
That's why Ubisoft Montreal developed the newly-revealed Spectator Mode, which provides many angles of viewing - not just player perspective. You can really see what's going on, which should be much more fun to watch, as well as providing a great learning tool.