at the first look 2 things are coming into my mind if i was a landlord. one positive thing and one negative thing:
the positive thing first: because relest is auction based landlord will charge maybe higher fees than on a "free market"
but
the negative thing is that the landlord has less options to choose who should occupancy his estate. this might frighten a few landlords
Landlord can choose a tenant.
Let's say a tenant wants to rent an apartment for $ 1000 and decides to take part in an auction for 4 apartments.

By the way, and you, the developers of the platform, already have some sort of a database of landlords? If so, how do you plan to expand it? It's me that at the moment very few potential customers of your platform are aware of its upcoming launch. So what are the channels for disseminating information and attracting customers (landlords, tenants) do you plan?
I apologize for the bad english.
There is no need to have a landlords' db, they will come to the platform later, after marketing.