I agree. I co-produced a documentary in 2002 (Prisoner of Paradise) and we made the decision to do a standard definition output instead of HD even though the film was shot in High Def. We saved a bunch of money, but I regret it now... The film got an Academy Award nomination for Best Documentary but it'll be tough to get the film noticed today because it's in standard def. We could go back to the original elements but it would be a huge time investment.
Better to pay the money up front and have a master that will have a longer shelf life. That being said, don't do it if the extra effort/money/time takes away from your story...
Drives and cloud storage are so cheap now, I would save yourself the time and hassle of this extra step (which will keep you away from actual filmmaking) and just keep the original files.
In my opinion, it comes down to one thing... How comfortable the filmmaker is. When you're young and hungry, desperate to prove yourself, that desire fuels your storytelling. When you're worth $100m, no matter how good your intentions and work ethic, that authentic connection to desperation and yearning is just not there. You're no longer in survival mode. LOTR and The Hobbit are good examples of this.