Same-day timing does not eliminate exchange mechanics.
A simultaneous exchange generally involves the relinquished and replacement transfers occurring together or in a directly coordinated transaction. While the 45-day identification issue may be less central where replacement property is received immediately, title, funds, closing instructions, counterparties and tax documentation still matter.
Many modern transactions still use an intermediary even when closings are closely coordinated, particularly to reduce funds-control risk and standardize documentation. The appropriate structure should be determined before closing.