Title insurance guarantees that you are receiving full legal ownership of the commercial property that you are buying. If a lien later shows up or it turns out some other property owner has the right to use your parking lot, you can sue the title insurance company to recover any loss that you have suffered.
Having a title insurance policy takes much of the legal risk out of buying a building. Usually the seller pays the insurance premium for this coverage but sometimes it is paid by both parties or the buyer alone.