What it genuinely does for a listing
A clean, finished garage floor photographs well and removes an obvious negative. Buyers walking through a garage with spalled, oil-stained concrete register it as deferred maintenance; a coated floor removes that impression entirely. That is a real effect on how a property is perceived, and it is different from a line-item return on investment.
The slab protection argument is stronger
Where a coating clearly pays is in preventing damage. A slab taking road salt every winter deteriorates, and re-pouring a garage slab costs several times what coating it does. Coating a sound slab before it scales is maintenance with a real avoided cost behind it.
If you are selling within a year
The honest answer is that a professional clean, a crack repair and a penetrating densifier gets most of the visual improvement for a fraction of the cost. We will say so on the site visit. Spending $5,000 on a floor you will not use is not something we want to sell you.
Want this answered for your slab?
Free site visit with a moisture reading, then a written fixed price. Across the BC Interior.