The difference between “testifying” and “answering questions” is an important one. So far, Kushner is merely agreeing to be “interviewed” and to “answer questions” — which is generally not done under oath. Kind of like the difference between being questioned by the police in an interrogation room and testifying on the witness stand in court.
Of course, anybody who volunteers to answer questions can still be subpoenaed to testify if the committee deems that appropriate. If Kushner lies now but changes his story once he’s under oath, that will raise questions. Kushner may be banking on not getting subpoenaed if he answers questions now, but one of the questions he’ll have to answer is why he had a meeting with a Russian bank that sanctions supposedly prevented him from having. His answer will probably be interesting.
I agree that this mess is stinking to high heaven, and an independent prosecutor is needed. Trusting the GOP to clean their own house when the mess could very well go all the way to the top isn’t a good idea, and the American people deserve to get to the bottom of this.