Almost everything in that report (with a couple of items) is already determined when you purchase a property. First off a home being in an official flood zone is a required disclosure under most disclosure laws. After all it is a potential detrimental condition of the property.
Next most purchase contracts have a clause (if the RE Agent representing the buyer did their job) specifying that the purchase is contingent upon financing acceptable to the buyer. One of the first things a lender will do is verify if it is or is not in a flood zone. The lender is then going to require the loan holder to purchase flood insurance as a condition of the loan. If that is not acceptable to the buyer they have an opportunity to kill the deal.
Thirdly, you’re exactly correct the buyer can easily look it up on the FEMA flood zone mapping system. I tell anyone I speak to that is considering making an offer to check this out, along with other checks, before making the offer.
About the only thing they are proving that the above items don’t is an aerial view and whether the property is within 1000 feet of the flood zone. As we all know aerial and mapping of virtually any property is free and available through many sources.