Multi-family valuation splits at four units under most lenders' rules: below that threshold, comparable sales with a rent adjustment still apply, while above it the number shifts to net operating income and a capitalization rate. Knowing which side your building falls on changes the entire pricing and marketing strategy.
Local knowledge also covers tenant relations, since The Residential Tenancies Act, 2006 governs showings and notice for an occupied building, and an agent who has coordinated that before avoids the friction that turns tenants against a sale.
That combination of legal, financial and street-level judgment is what an algorithm cannot replicate. Get your hand-reviewed valuation from Joel Dyck.