She wants to get us out of endless regime change wars, and has a personal stake in it. That is compelling enough for me.
As for her take on the impeachment issue, she indicated that he did use his power for his own benefit in trying to get a foreign nation to look into a political opponent. So she acknowledges his wrong doing. But she also said that she didn't think most people who read the transcript would think it was impeachable, and was afraid it would divide the country and result in a backlash for the Democratic party if people saw this as a political ploy.
Since the Senate is controlled by Republicans she is probably calculating that he will not be removed from office, and if it was spun enough it could be used as a campaign tool for Trump.He already raised a lot of money off of the issue.
Either way, things are going forward it looks like. If they find more information it may change the calculation.