system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why was the American Mafia interested in vending machines?

I have seen this referenced in a few gangster movies, Goodfellas, Black Mass, etc. But I don't understand why they were so interested in vending machines/coin-op machines specifically. Am I not realizing just how much money one can legitimately make from selling soda? If that were the case wouldn't a legit business be more efficient and better suited than the Mafia?
gpt
It's a cash business.

The mob makes a huge amount of money through illicit dealings, but to spend that money later they need to "launder" it by finding a way to claim it as legitimate business income.

Enter the all cash business.  Since there's no real record of what the machine sold or for how much, you can report the illegal cash as vending machine income.

That makes the money safe to use without attracting the attention of the IRS.