Does an e-commerce site search really need anything more than fuzzy matching on item names? It pay not be perfect, but if it provides relevant results 90% of the time, you're paying a big premium for SaaS search that may only net you a small tail end of additional sales.
In particular for ecommerce sites it pays to invest in search. A large percentage of transactions is initiated by search queries. You are correct that fuzzy matching will likely get you decent results. However, finding the right product 90% of the time or 98% of the time makes a huge difference if you have a high volume of transactions. Synonyms and a better spelling model can massively improve your results and the resulting conversion.
But search relevancy is only one part of the equation. Think about a physical store and how the milk is usually in the back and a few high margin items are close to the counter or strategically placed. The same can be true for an ecommerce store. If the search engine has the ability to take business metrics like revenue and margins, or customer data like loyalty programs or brand affinity into account, you can much better optimise for your desired business outcome.
We just recently switched one of the largest ecommerce retailers in Australia over from Algolia to Sajari by doing the above and increasing their conversion rate by 10%.
