It relies on things being correctly tagged. Over or under tagging will reduce discoverability. If you have a product (or tag) that is loosely defined or changes

It relies on things being correctly tagged. Over or under tagging will reduce discoverability. If you have a product (or tag) that is loosely defined or changes over time, this can cause issues as well. It's easy to do this for something rigid like technical specs. but if you have ever looked for something hyperspecific (e.g. multiple tags) on a site such as Newegg you've no doubt had some run-ins here and there with incorrect tagging. This is further exacerbated if you allow individual vendors to do the tagging of their own products, who will have a perverse incentive to do "SEO", or may not spend enough time/effort resulting in undertagging. Often times what you are left with are only a handful of "high-level" tags/filters that don't actually filter much, forcing you to spend more time looking at and evaluating multiple products (which marketing/sales teams of companies probably view as a net positive). TL;DR: Filtering is an absolute boon when there is proper tag curation. Edit: I should clarify that I think Newegg is really solid as far as tagging is concerned, but the fact that this occasionally happens even in that environment just goes to show that it requires effort to do right and you may not get 100% discoverability.