Oliver Burkeman: Want to resist purchases you’ll regret? Use physical money. The problem with the ‘frictionless’ future is that friction can be good. Silicon Valley is getting all excited again, in its Silicon Valleyish way, about the future of how we pay for things. The specific cause of excitement, this week, is the news that Richard Branson has made an investment in Clinkle, a mysterious startup that promises to revolutionise payments in some unspecified way, possibly by letting people send money from smartphone to smartphone using sound.