It's how you get spacecash in a jam. Not exactly sure the real use case but I like seeing them at gunshot gas stations.

There's no risk of charge back because the cash is in the machine. So we can send the coin to you instantly.

For example if you wanted to bet with bitcoin on a sporting event (which is legal in the US). You might want to fund your account with BTC as it can be quicker than using bank deposit depending on the sportbook.

Using a bitcoin ATM allows you to have the coin immediately, versus signing up for Coinbase and them holding onto your coin until the ACH cannot be charged back.