When a catalog has several similar products, reusing the same description across them can feel like the obvious shortcut. Same category, same rough specs, why write it three separate times. In practice, it tends to cost more than it saves, in ways that don't show up until someone's actually comparing the listings side by side.
It's obvious to a shopper comparing two of your own products
A shopper deciding between two similar items on the same store will often open both listings in separate tabs. Finding the exact same paragraph on both isn't a small detail to them, it reads as a sign that nobody actually differentiated the products, which raises the question of whether they're actually different at all.
It gives search engines nothing new to index
Two pages with substantially the same body text don't help each other rank, they compete with each other for the same relevance instead of each one having its own reason to show up in a search result. A catalog full of near identical descriptions ends up with fewer pages that actually rank well, not more.
The fix doesn't require much
Two products can share the same underlying template and still each get one or two sentences that are actually specific to them, what's different about this size, this material, this use case. That's usually enough to stop reading as duplicated without requiring a full rewrite of every listing.
This is what PagePolisher's duplicate description check looks for: not just similar wording, but the same description showing up word for word on more than one listing in the same scan, so it's easy to catch before a shopper, or a search engine, notices first.