Visa has at least 343 million cardholders worldwide.
Of course trying to determine crypto "users" is essentially impossible but even the most bloated and inflated estimates (users unique per chain, address = user) put the number somewhere around 300 million. Personally I think it's more like 50-100 million by the time you factor in users on different chains, different wallets, etc. I've spent a lot of time analyzing chains to come to that number, it's not difficult. Nearly every crypto user participates on more than one chain and often uses at least two addresses (hot and cold wallet, for example).
Sure enough, the quote is right there in the report:
"over 25 million blockchain addresses held over $1 in stablecoins"
25 million addresses, which absolutely don't equal users. Even if they did, that's .05% of global internet users (5.2 billion). With the threshold for inclusion at $1...
Of course you say "moving as much value" which doesn't necessarily correlate directly to users or their activity but I would venture to guess (if the report is accurate at all) that a substantial portion of that stablecoin "value" volume isn't anything resembling the economic activity of Visa where every swipe is in exchange for a good or service. At best settlement between exchanges but also wash trading and all kinds of weird hijinx that are basically just swapping tokens around with no other meaningful economic activity. Just look at chain analysis breakdowns on the latest crypto heist and watch them tumble it through stablecoins at least once (often many more). I guess that's "value" but I certainly wouldn't be touting it.
The crypto narrative of helping the unbanked is essentially PR damage control spin to try to counter all of the obvious evils that crypto is directly involved in and often responsible for. This volume (if even accurate) has nothing to do with helping regular people, the oppressed, the unbanked, whatever.