What rent by the room means in practice
Renting by the room usually raises the gross rent one house can produce, because bedrooms priced individually often total more than a single whole-home rent in the same market. It also multiplies the work: more leases, more deposits, more move-ins, more door codes, and shared bills that have to be divided. The system of record has to treat the room, not the address, as the rentable thing.
Example
A house that would rent for $1,600 as a whole home is instead rented as four bedrooms at $525, $525, $600, and $650, each with its own lease and deposit.