Not exactly real estate agents for buying/selling but related:

I remember reading about the fact that, at the time, most apartments in NYC were "broker only" (aka you can only see and then rent an apartment if you are using a licensed real estate broker).

The more I thought about this, I started to see the benefits for both sides:

- for the landlord: the broker acts as a filter for people who are serious vs "looky loos" (actual quote from a real broker)

- for the tenant: the broker wants repeat business so they will, in theory, only deal with reputable landlords

- for the tenant part 2: if you are a busy, hard working individual, the broker acts as your "agent" (in the principal agent sense of the word) to save you time by going and finding apartments for you so that you can focus on your high paying job.