The point is she had nothing--repeat NOTHING--to say other than what she had been told. What somebody else tells her is considered hearsay evidence in any court in the land and is unadmissable as evidence because hearsay evidence is almost always unreliable, suspect, or blatantly false. You can quote what somebody said under oath, but not just stuff you heard or was told. And the fact that she testified in a way that was almost certainly coached and memorized further makes her testimony suspect.
When Schiff pulled this kind of crap in the collusion hearings, there were competent cross examiners on the panel who got every single witness to admit they saw or heard nothing specific that was illegal in any way.
Schiff didn't make that mistake this time. They made sure there was NOBODY allowed on the commission that would challenge these witnesses in any way as well as making sure no witnesses that wouldn't trash Trump would be called and no exculpatory evidence is allowed. They're using edited video, quotes taken out of context, and manipulated testimony that should appall every honorable American.