Everyone likes to talk about how markets give you all sorts of sales boosts.
If you ask me, markets were pushed because suppliers made more money on it. You're converting vending machines which were bought once many lifetimes ago, into something that generates recurring revenue for the supplier in monthly fees, in payment processing, in other ancillary services (like theft monitoring).
Sure, you'll likely get a sales boost of 20%, 30% perhaps maybe in some areas. You'll also get a headache in theft, which you have to manage. And now you're paying kiosk fees of maybe 5% to a 365, payment processing to them too for another 5.95% or so (with no cash discount to recoup any of it), $100-150/month to Panoptyc to monitor your cameras, additional labor cost compared to vending.
You'll probably net out a bit more at the end of the day. Whether it's worth it depends on the client and on your operation.