That doesn't make it gambling though, any more than getting a capsule with a random prize or a pack of trading-cards for MtG or Pokemon is gambling (though in the case of TCG it comes much closer to gambling due to the potential for selling on high value cards.)
There's a problem with gambling that loot-boxes don't have, and that's the fact it presents itself as a solution to the problem it has caused. When you gamble or overspend on anything else there's a chance you can spend the money you needed for more important things (rent, bills, food etc.) However only gambling offers you a way out, if you bet with the rest of your money you might win back what you lost and solve the problem. If you lose that, well you can always take out a loan, but if you gamble with that loan you might make enough to pay back the loan and your bills and have some left. No-one has ever regretted spending their rent money on FIFA and getting the wrong players, but thought if they borrow some more money and get the correct player it will solve their rent problems.
TL~DR Gambling for money is different to loot-boxes because money is more important than a piece of digital crap with no real-world value. Obfuscating the two is just a way of regulating video games because "think of the children" while failing to tackle the real problems of gambling and predatory marketing with microtransactions.