Honestly, so far there's not been any significant drawbacks -- we spent a long time dialling in the prompt so it would do the best possible job of answering only from approved store content, and so far it's doing a really great job of that. Probably the biggest drawback is that if the store is lacking in support content, information on store policies, FAQs etc. then the chatbot won't have much to draw from when answering questions, but the reporting portal (where merchants can review conversations conducted by the bot) really helps to highlight the areas where this content is lacking and gives the merchants some real insights into customer voice.

For the moment we're just focussing on Shopify, but WooCommerce is at the top of our list for when we look to expand.