Is there significant value for the buyer to have a broker?

With the free, public access to listings and historical data (e.g., StreetEasy), is it really valuable as a buyer to have broker? Certainly, it cuts into the commission the seller's broker will make, so one would think there would be more flexibility to get a slightly lower price on the apt if only one broker is involved. Also, more incentive for seller's broker to bring our offer to seller, since the seller's broker doesn't need to share commission with buyer's broker. Do buyer's brokers even have access to apt listings that are not published on StreetEasy and other such sites? Just not sure what value they serve, particularly on the lower end of the market. Assume under $1MM transaction.