As a listing agent, I will open the door, as a courtesy to the buyer agent when that buyer agent would be there in person if possible. Example: A Realtor w/ a good reputation who works diligently showing their buyer properties, but is unavailable on a given day and their buyers need to see it that day.
For the buyer agent who driects their clients to have other Realtors show them properties with the intention of simply writing the offer, I say, "On behalf of my seller, I will gladly show the property, and the referral fee to the buyer agent is X."
In order for a buyer agent to effectively counsel their client, the buyer agent needs to be actively looking at the properties on the market. The buyer agent needs to be able to compare properties that buyer has viewed in order to help the buyer. Part of what a good buyer agent does is keenly listen and observe a buyers responses to a proerties about what works and what does not work for them. Really good buyer recalls and recaps the strengths and weaknesses of a property in accordance to the buyer's priority lists. The buyer agent will also provide feedback about the marketplace on a regular basis. The buyer agent gets to know his/her clients and makes suggestions to the buyers as they look at properties.
While the fees for a buyer agent are paid from the seller proceeds, not sale happens until a buyer buys. In essence, the buyer funds the expense. You deserve good representation, counsel, and market expertise for the fees that your purchase will ultimately fund in form of the buyer agent commisison. Don't shortchange yourself. Choose a good buyer agent and expect that person to work on your behalf, and that, by all means, includes personally showing you properties.