For example, I cannot see a necessary huge drop in crypto gambling despite the presence of COVID-19.
What about several million people facing the prospect of no income? Unless you're a total degenerate, and there must be plenty of them, you're not going to continue gambling if you're wondering how you're going to manage to feed yourself.
Similarly I presume the lower than expected dip in merchant stuff is people buying necessities.
I must be assuming that those who are spending much money in gambling are those people who are not at the economic bottom of the society. A month-long lockdown might not really make them a total destitute. On the other hand, those who are daily wage earners will have to minimize, if not stop altogether, their gambling habit. I suppose the main revenue of gambling sites do not come from small time rollers who often just resort to faucets whenever their wallets are emptied earlier than usual. But then, as squatter have pointed out above, there are initiatives done by different countries, their labor departments or agencies, and even their private employers to somehow maintain the workforce's income despite the crisis.