Why would these companies want a private blockchain instead of using a database and a history table? Or even more simple, timestamp log files? Is this many comp

Why would these companies want a private blockchain instead of using a database and a history table? Or even more simple, timestamp log files? Is this many companies coming together to put clearinghouses out of business and therefor needs this technology to establish better trust among the players? Unless I'm missing something, it appears to just be hype with people saying build it with blockchain?