It's pretty common in the USA that landlords want to know your credit history before they let you sign a lease. They want to know how much you make as well as how much debt you have so they can verify your ability to pay rent. Tenants tend to have pretty strong protections in the USA (some states more than others), and the cost of having a bad tenant can easily run into the tens of thousands of dollars.
The landlord usually has fixed costs that continue regardless of whether or not they're paid (mortgage, insurance, certain utilities), so if a tenant refuses or is unable to pay their rent they're not just out the cost of that rent, they also have to pay those substantial fixed costs out of pocket: essentially they lose two month's rent for every month a tenant doesn't pay. If the tenant refuses to move out then the landlord needs to go through the legal process of eviction, which can take months or up to a year, all the while the tenant isn't paying.
My only concern about your story is that the landlord wants you to submit your credit report to them. Typically the credit report is gotten directly from the credit bureaus, otherwise you could falsify the information and send him a fake. All of the major credit bureaus in the US market their services directly to landlords:
Your landlord might ask for your social security number (or whatever your country's equivalent is). However, services now exist that allow your landlord to get your credit history without handing over your personally identifying information. The landlord just needs your email, then the credit bureau verifies your identity directly and sends your landlord a verified report that does not include your personally identifying information.