Because it is registered with ISC rather than just agreed verbally between two neighbours, a buyer's lawyer will see it during a title search and can explain exactly what it does and does not allow before the deal closes, rather than a new owner discovering it the first time a car is in the way.
Maintenance responsibility, snow clearing and who can park where are the practical questions that actually cause disputes, and a well-drafted easement addresses them directly rather than leaving both sides to work it out informally after a problem shows up.
An easement that only exists as a decades-old verbal understanding between two now-different sets of owners is a common source of a closing delay, and it is exactly why a $400 to $600 home inspection alone will not catch it, a title search will. Get your hand-reviewed valuation from Joel Dyck.