The inflation targeting framework lends itself well to the separation of instrument and goal independence, in that generally central banks do not have goal independence (as the target is usually, but not always, set by government), but, in order to prevent the so-called political interest rate cycle, central banks have independence to pursue the mandate given to them.
It is possible, as the use of physical cash declines and technology advances, that central banks will find it strategically better to shift to making small but regular changes to banknote design and functionality rather than large, decades-apart upgrades to a full banknote series.