Tying the disaster fund directly to Gulf oil revenue has obvious political advantages for the company, as the Journal pointed out, "because it could make the administration and BP partners of sorts in developing the Gulf." It would forestall measures such as the bill passed by the House of Representatives last month effectively banning BP from new offshore drilling in the Gulf, because such a move would then threaten the stream of revenue for the disaster fund.
The White House never considered commandeering the assets of the corporate criminal, instead allowing BP to retain control of the disaster site through a series of failed attempts to shut down the oil leak. It has persistently downplayed the possibility of prosecution of any executives from BP or its partners in the well.
All of this is pretty predictable, in light of the fact that BP was one of the most significant contributors to Obama's presidential campaign!