My OpenSUSE experience is limited, but while you’re waiting for a response here is my understanding:

If it’s working and you value stability, don’t enable it. It can cause occasional conflicts.

But if you want best efficiency (and maybe battery life, for example), you could enable it.

I personally will not enable it unless there is a need. It’s potentially one more thing to micro manage.

Now if I was in my 20s again and had the time and passion for reinstalling the system, I would absolutely enable all the things and find out the limits, pass them, break stuff and reinstall with the new knowledge :)

Yes, there are apparently some different scenarios (perhaps DRM? I forget) where the non-free codecs in Packman are better. I would install them, just be aware when you do zypper dup that Packman will often lag behind other repos in the version number and you should choose the option "keep obsolete" when resolving the conflict, otherwise you'll end up with a mix of codecs from the openSUSE repos and from Packman.

https://en.opensuse.org/SDB:Installing_codecs_from_Packman_repositories