The April 25th, 2016 episode of Hotel Impossible titled "Futility Closet" included mention of how a point of sale system can increase bar revenue. If I heard correctly, host Anthony Melchiorri mention a sales increase of around 30%.
I can vouch for that from personal experience - just the sight of a point of sale system in a bar, restaurant, or retail store can curb employee theft (employee theft accounts for around half of all retail theft in the US per the National Retail Federation).
In the past I can recall a nightclub and bar that spent just over $50,000 on a very basic point of sale system and the owner reported back to me the the system paid for itself the very first weekend - that is how much the owners employees were stealing from him or revenue that was being lost due to employee errors!
Kudos to Hotel Impossible and Anthony Melchiorri for mentioning one of the key benefits of implementing a point of sale system in your bar, restaurant, or hotel!
Are you in the US and in need of no cost retail point of sale advice? I'm happy to help and can be reached on my cell at 208-340-5632 (I am on Mountain Time) or via email at firstname.lastname@example.org. There is also a contact form to the right that can be used to reach me.