Every person you talk to will have a different opinion on this subject - some would argue that open houses only attract nosy neighbours and buyers who are just starting the home buying process or doing market research, so not the best people you can attract. There is also the argument that open houses only benefit the listing agent who gets to meet potential clients to grow their network. Other agents will say it's not the best use of their time to host an open house, and therefore will suggest against them.
I agree that buyers who are willing to call to book a private showing are probably your best leads, however, in my experience there are also many serious buyers who prefer not to schedule a private appointment; they just don't want to bother anyone until they can have a preliminary look at the property, especially if the house is a fair distance away. With the current market slowing down and buyers not feeling rushed to make a purchase, showing requests are far fewer in between. Sometimes, the only way to generate any traffic is through an open house. It is becoming less frequent that your house sells within the first few weeks, as average days on the market are now longer.
Even though an offer may not materialize directly from an open house, you may actually have influenced someone to start the process. I have had 2nd showing requests come in from buyers who were at a previous open house. I have also had buyers whose family or friend live on the street and encouraged them to take a look. It's actually no surprise that in certain neighbourhoods, you'll have buyers purchasing homes because they know someone who lives in the area. Therefore, having neighbours come through an open house is not the worst idea.
Also, booking an open house allows for greater advertising exposure. When you schedule one, you can place your listing on more online pages, which adds a sort of spotlight on your property. In addition, most papers will have a special section designated to open houses, giving these listings better visibility to the public.
Of course, not every house will generate the best action from an open house depending on its location. But if it does make sense, it wouldn't hurt to host one as it can only potentially attract a buyer, and creates a buzz as people will be talking about your property.
Any questions? Please don't hesitate to contact me directly.