New courses are simply fun to play, even when the course is poor quality. There is always some level of excitement in seeing new features and holes for the first time. Even on courses that have been seen before, the excitement exists in seeing new features that were missed previously. New courses also provide variety. This variety can be anything from different shot types into greens to having to shape shots off the tee when that may not be required at the home course. Playing new courses, seeing this variety, keeps the golf game sharp by having to play new and different shots, rather than the same ones time after time.
Sometimes, though, I find myself going to new courses to see specific things. Perhaps, it may be that the course is generally highly regarded and worth seeing. It may be that a course is worth seeing because it was done by a specific designer on a specific type of site. But these courses are visited with a specific purpose and desire for growth in course design knowledge.
At all times though, for the same reasons skydivers jump and climbers climb, I play new courses simply because they are there. Most of the time, I really need no reason to play a new course beyond the fact that the door is open and the cash drawer accepting of my money.
I don't intend to ever stop playing new golf courses....well, unless I manage to play every golf course that is currently in existence. Of course that will not happen. It is simply too much fun to go and play new golf courses, either with friends or with strangers who I meet on the first tee. That is one of the great joys of golf.