Then, is refresh rate important for WoW?
Yep. You'll see a lot more of a difference in more fast-paced games. WoW's too slow for you to get much benefit from a higher refresh rate. If you don't spin the camera around much you won't really notice a difference in wow, however if you play other games it may be totally worth it.
Furthermore, is 60Hz good for programming? Don't worry about refresh rate if you aren't big into gaming, 60hz is more than good enough. I do a lot of programming and I feel like higher resolution is appreciable. I have a 1440p 144hz as well as a 4k 60hz, and I usually work on the 1440p one. Otherwise, if you want to spend a bit more, go for 1440p ultrawide.
Beside above, does World of Warcraft need 144Hz?
144hz is perfect for WoW because of all the fast camera movement which is so much nicer when it's smooth. Gsync is an important part as screen tearing ruins the smoothness, and you won't be maintaining 144 in cities.
Does FPS matter in WoW?
While you can not see the single frames, moving things will seem smoother. Assuming the game can run at 120-144 FPS. Online nature of WoW plus it servers will often prevent that. Yet for high paced M+ or raid you can get more than 60 FPS on a tuned PC.