Watching the Amateur at Riviera yesterday, finally got the explanation that I've been looking for regarding #12 at Chambers.
The 10th at Riviera was the major hole played while I watched and the strategy of the hole was well discussed. The piece I took away was that for amateurs, the driver was the better play. Driver meant you only needed to hit one good shot. The lay-up required a well placed tee ball AND a great approach to get par. My assumption is that for the pros, they hit any shot they attempt, well, like professionals, and they can get away with whichever strategy works best for the pin position.
To Chambers #12...I've bemoaned the hole with my cronies, because driver seems the only play to me. The lay-up requires an accurate tee ball from the amateur, which then leaves a blind 2nd. If the 2nd isn't perfect, a 3-putt is very much in play.
I've never played Riviera (and I'm not putting CB#12 in the same class as Riv#10), but it seems to provide a greater option off the tee, which seems to be the ideal for a driveable par 4. My experience with driveable par-4s is limited, but I really liked Dismal River White #8. Drive the green, play to the fairway for angle of approach, or play to the fairway with distance to leave a short approach.