LLs can have openings at any time of year or even at any time of the month. How could you have a tenant who could move in immediately (so there would be no loss of rental income) when they don't know when a unit would become available to them? How could they give their current LLs the required amount of notice to vacate?

Who would screen the application? Would this be done by you or by the LL himself? Who would pull the criminal background checks, the credit reports, verify employment and income, get references from current and past LLs, verify the current & former addresses of residence, and so on?

What standards could you use to qualify tenants? Every LL uses different criteria based on his own needs. Some accept pets, smokers, small misdemeanors, medical judgments, etc. Since you could not possibly know every LL's criteria, how could you state that the tenant would be qualified to rent from me? Would you guarantee that?

Or would you merely provide an application, with no guarantee of any kind that they could be qualified? Agents do this now. They submit applications and are paid a fee (up to one month of rent) if the applicant is approved and moves in. If all you provide is applications with no guarantees, any agent can already do this. There would be little value in it.