Their basis for holding back was Ukraine might use them to strike targets in Russia, and that cannot be allowed..
That was one argument, the other one was that a (German) ground force maintainance crew & training & encoding experts and stuff would be needed.
Regarding sending maintainance crews, the opinions seem more and more positive of late. I'll reckon we'll might see Taurus , and hopefully more of it's friends, being send. Then again, it will also depend on the outcome of the ( EU) elections this year.