Yeah, I don't think its particularly useful with hostile cloud providers that want to keep their legally unchallenged discretion over which of the clearly-not-inteded invoices to cancel and which ones to enforce.

But is is useful in related cases. I have now had two separate incidents where this would have saved me the hassle. Both were service providers which unilaterally tried to deviate from contract terms. One was possibly a unintended billing software upgrade where they suddenly added an extra item to a 10 year contract that did not belong there, the other was an apparently profitable "lets just try and see what percentage of customers notice" dick move. I should not have needed to care about this, both companies should have just been slapped with a hefty fee for requiring their and my bank to take a look, and then figure it out on their own instead of me having to call once to fix the problem for the future, and then call again to remind them about reimbursing the delta from past billing intervals.