Cryptocurrency detractors claimed it would be impossible to handle the volume of Visa or MasterCard. 

Lightning Network is disproving them, it is a matter of when not if Digital Assets will significantly challenge fiat currencies! With transactions costing pennies or less and to be able to use your phone, Lightning completely changes the way money is moved. If banks aren’t paying attention yet, they will be when they look at Lightning payments and realise they are likely to be disrupted!