Will the Prosecutors Still Get a Bunch of Useful Information From the Trumps?

The president's lawyers have suggested that they plannd to advise him to exercise his fifth amendment right to avoid self incrimination during his deposition. To what extent does this change the prosecutor's strategy in these depositions, can they still get a bunch of useful information? Or what what happens then? They're not going to get a lot of useful information from the trumps. And the eric trump has already been used. So i don't think anyone really expects them to answer any questions.