You could (for example) buy a house by using the money as a down payment. Useful if the timing of lease ending/buy opportunities don’t line up with savings schedule. Smaller opportunities for house renovations or remodels etc.
You could invest that cash flow up front. 2020 was a very profitable year in the stock market... especially if you invested after Feb 20th. You’d make more money than if you invested in 24 chunks bimonthly. So if you had this service you could make some money when you see an opportunity (also risky). “Time value of money”.
On the smaller scale, you could use a similar advance service to semi-monthly buy bulk food purchases if you typically don’t make enough to afford big shopping trips. Not everyone is wealthy, and being poor is expensive. Being able to buy food you know you use in bulk will be cheaper per meal, you just need enough in your checking account to afford that one big expense.