I used to work with Dermalogica and I did "Skin Bars".
I didn't leave products out all the time, but once a month I would set up a table, chairs, mirrors, headbands, lavender scented estee wipes and products so I could guide people through giving themselves a mini-facial. I was in an environment where many people came into the building for other services so I would connect with them and have them sit at the table on their way into the building or on their way out. I would ask a few questions about their skin , the products they use and their main skin concern. I then handed them the products best suited for them and while they were using them I educated them on how the product would benefit them. Start with a cleanser, exfoliant, serums, masques, eye product etc. I had a product display and also offered a discount if they scheduled a service with me before they left.
I also did skin bars where I sent out invitations to clients and made a big event out of it. I had chair massages, prizes, discounts and hand treatments all going to expose them to different services and products they may not have tried.
In my experience, having products sitting out on their own didn't raise my retail sales like a skin bar did.