Hadit, there is nothing to leave aside, the issue being quite clear what are the powers and extent of them.
Obama will do it just to end the investigations.
Everyone would plead the 5th and smile at the committee chair persons.
The public would grow very tired of it very quickly.
A pardon would remove the criminal consequences of an action, and that would effectively remove the constitutional protection against self incrimination, so those pardoned could be compelled to testify under threat of contempt of court. The purpose of the investigation would then be to uncover the extent of a criminal conspiracy between the Justice Department, the State Department and the WH with the Clinton campaign to cover up crimes committed concerning the secret, private email server and Clinton's other possibly illegal machinations at the State Department and after.
It is unclear how many indictments of people lower down it might produce, and it would probably not be as much of a page turner as the Starr report, but it would hold the public's interest for some time and produce a ton of baggage Democratic candidates would have to carry in two years, four years, six years and perhaps even in eight years.