Lee is a role player in the mold of Ariza, but with more upside. Ariza proved last season that he cannot carry a team, but was being paid as a star at over $6 million per season. Lee makes only $1.3 mil and is almost as good as Ariza already. The Rockets also got a $6 million trade exception and Les Alexander has already given Daryl Morey the green light to spend it. Let's face it - championships are won with money, and this gives Morey some flexibility.
As does Ariza, Courtney has his flaws. He does not score well off the dribble and as Martin's backup, he will be called on to do that. Lee shoots 83% from the line, so I'm sure Adelman will be working with him to get him there more often. He is a good set-shooter and can hit the three, especially when the defense collapses on a driving Brooks or sags down on Yao and Scola. Mostly, though, Courtney Lee plays defense. Defense doesn't pay as well, but it wins games.
So the gameplan looks like this. Start Martin and Battier. Offense and defense. Bring in subs Lee and Budinger. Defense and offense. As long as you have both roles on the floor, you can always shut down an opposing scorer.
Ariza is a good player, but he is a luxury. An all-around player that specializes in defense is a boon to an already great team, as he was to the Lakers. But he is not a go-to guy and therefore not worth $6 mil. Good decision, Daryl.