Many tenants that are employed with enough income find a security deposit a barrier to entry.
Prospect tenant applies and qualifies to lease an apartment. A security deposit and the 1st month's rent is required. Prospect tenant only has the 1st month's rent but not the security deposit. Landlord says, "That's alright, I can take out a guarantee with Jack and Landlords on your behalf and I'll be covered for damages up to your first month's rent amount. But you tenant will still pay the cost of the guarantee each month in addition to your rent to me. After I receive your rent each month I then pay the guarantee company. The cost is 65% of a month's rent paid over 12 equal payments. After the twelfth payment, it drops off and stays effective until you terminate your lease. It's non refundable but you can lease today."