With stories that are self-contained a show, if it runs long enough, is easier to sell to independent stations or outside markets. That way they don't need to keep the episodes in order.

But if a show is popular enough it can be shown out of order and still snag viewers, and with something like ST, which has established characters, viewers can pick up on the story quickly enough even if they are shown in random order.

MASH is like this. Castle is as well.

James Bond began this trend with Goldfinger. The previous films built on each other but Goldfinger can be understood on a stand alone basis. Each Bond film after that went for the same thing until the series re-boot with the new Casino Royal. Now it helps to watch the films in the order they were made to understand the current Bond.