I heard someone yesterday, and I've overheard many people before, complain about outpatient surgery. The criticisms surround insufficient care by the hospital. In other words, they perform a procedure then ship you back home to fend for yourself.
While some people would no doubt get some risk reduction, greater peace of mind and extra care from staying in a hospital for a day or two, there are costs involved. There is obviously the financial cost of keeping a patient in the hospital. There is a cost to the patient in terms of comfort. I've yet to hear anyone actually want to go to the hospital when nothing was wrong with them (aside from Grandpa Simpson on one episode of The Simpsons) and I've never heard anyone say how comfortable hospital beds are. There is also increased stress from being away from home.
In my mind, the greatest benefit of outpatient surgery is that it gets you out of the hospital. Hospitals are full of sick people. The sooner you can get out of there, the better. For anyone who has ever worked with fresh from the sale barn feeder cattle, you know the worst place fresh cattle can be is confined in pens at your barn. If one gets sick, the entire bunch is at risk. The sooner you get them out and away from that environment, the better. If you can recover at home, I find it hard to imagine why anyone would want to stay in an uncomfortable environment surrounded by sick people.
This may be a cultural element from the days when you were kept in the hospital a few days for most any condition. I'd be interested to see if the attitudes toward outpatient surgery are different for people in their 20s and 30s versus senior citizens.