Street Fighter V wasn't a huge hit for Capcom and the company has stated several times since that it has underperformed sales-wise. Now the publisher is trying to mix things up a little and they've decided that one way to do this is via loot boxes.
By spending 500 Fight Money, you'll get a Fantasy Fortune Reading that Menat will perform for you, which in reality means random items. Those are either cosmetics or things which will help you get further in Survival Mode. That is single-player only, so while it will help gamers getting further, you won't risk facing another person boosted by loot box items online.
It's worth pointing out that you can't buy Fight Money with hard-earned cash, as this is the currency you use to unlock new fighters and stuff like that, and you earn it by playing. On the other hand, by spending your Fight Money on loot boxes you'll have less for new fighters and those can be bought with real money. Clever, Capcom!
Whether or not loot boxes really are the secret sauce that will make Street Fighter V more popular remains to be seen. The loot box update is releasing on June 25, so we'll find out thereafter.