Money must be involved in gambling be it directly or indirectly, it is important to note that you have to use your money to bet either you loss or you win that's what makes you a gambler, something must be at stake for it to be gambling if not is not gambling, you most have something that you may loss before you call it gambling.
Actually gambling doesn't have to be with real money either because there's a lot that can be at stake besides money, for example in the form of assets or favorite things and so on, that's why the OP said whether it can be called gambling if there is no real money or money, I say YES even using fake money it can be said to be gambling because putting something at stake does not have to be real money because I have gambled also with fake money.
Money has always been the main subject in the world of gambling and where all online casinos as well as land-based casinos and other gambling platforms use money and do not use anything else, because money is something of value to anyone for bookies and gamblers.