Chat bots don't belong to an e-commerce site; chat bots belong on the outside, specifically to comparison-shop and pull in some external information to de-bullshitify offers, correct "mistakes" and "accidental omissions" in the listings, resolve the borderline-fraudlent crap companies play these days with store-specific and season/promotion-specific SKUs with different parameters all resolving to same model/make name (think Black Friday/Cyber Monday deals that are not actually deals, just inferior hardware with dedicated SKU).

The use case for chat interfaces would be as follows:

Grandma wants to buy a good bike, but doesn't know about types of wheels or how many gears they need, or what type of frame is appropriate for their body type.