For the buyer, a lease-option lets you take possession of a home today by lease, and then buy later as your credit and savings improve. The set-aside from the monthly rental payment is a forced savings plan. At the end of the lease term, you'll have a pot of money which can be applied to the down payment. If you choose to walk-away from the sale at the end of the lease, you will lose the pot of money as it stays with the seller.
For sellers, there is more risk than benefit with a lease-option purchase. You have a lease tenant, but you may or may not have a sale at the end of the lease. Not every lease-option makes it to closing. As compensation, you'll have the buyer's down payment, but you won't have a sale. Plus, the condition of the property may require repair and improvement to ready the property for the market.
Lease-option purchases happen infrequently for a reason. There may be some advantage for a buyer who has no other option, but the risks outweigh the benefits for sellers.