Modules, widgets and what each can answer
Live-chat modules from drupal.org connect your site to a staffed chat box. Fine if someone is always there.
Universal widgets added through a block or a template hook work with any vendor, and read what is published rather than what is in your entities.
A native module connects the site to an assistant that trains on your content and, on Drupal Commerce, answers order-status questions live.
The distinction matters more on Drupal than on most platforms, because so many Drupal sites carry deep documentation, policy and programme content that visitors genuinely struggle to search.