It is £150 million (reportedly)
I think Joe Lycett's stunt is a good one, as you say OP why are people more bothered about Lycett and the £10k than Beckham and £150m? People seem to be getting angry about the wrong thing.
And yes it's a waste of money to shred it (if it was real money). But would people be saying that if Lycett, or any other celebrity, had bought a £10k watch or phone or any of the other things people spends thousands of pounds on? Or if he'd just let it sit in a bank? No-one would be moaning about how he could have given it to charity then.