The benefit to this change is that the majority of visitors to an open house are there because they intend to be... they didn't just happen upon it. They already know the number of bedrooms and it already has the number they need. They already know the price and it already is within their range. This is a house they already know they would consider buying.
If your Realtor is not holding your house open and doing it often then call me. Historically I haven't sold a lot of houses at the Open, but I have a feeling that is changing and changing fast. The age of real estate information is creating a "new normal", indeed.