A registered easement gives a buyer certainty about who can use the driveway and under what terms, and your lawyer can pull the title through Information Services Corporation, typically for a fee in the same range as the $800 to $1,500 in legal work a closing already involves, to confirm it exists and matches what is actually happening on the ground.
An informal arrangement with no registered agreement is a much harder sell, because a buyer's lawyer will flag the lack of documentation, and it can affect financing if a lender is uncertain about the property's boundaries or access rights.
Getting the title and any agreement documented before listing, rather than explaining it verbally during showings, avoids a condition-period surprise for the buyer. Get your hand-reviewed valuation from Joel Dyck.