Cybercombat is definitely not required to be a hacker. Not getting caught is more important. The big problems with cybercombat are:
1) Frequently, cybercombat means you lost. If you hack into a system to do something like conceal a break in, and then cyber-punch everyone in the face, it didn't really help.
2) You can't make people fight you. Black IC sadly doesn't work very well, here, because you can always jam yourself offline. And nothing really stops people from AR hacking and thus having no real consequences for losing cybercombat.
3) There are almost always better ways of dealing with opponents, or there are better ways for them to deal with you, such as just kicking people off the system, unloading IC using admin powers, or the like.
4) Agents can do it for you, and probably better than you too because of Cascading.
Point 2 is mitigated, a bit, if you are so rad at cybercombat you can oneshot people, but that's actually very very hard as a hacker.
Now, it's not true that cybercombat has no uses. But if I had to pick one hacking related skill to not have, it would be cybercombat, no contest.