The functionality of the "Actions" section of tables is pretty much a more rigid version of a custom column button. Retool users just starting out often opt for the Actions section as opposed to the custom columns, but then can't perform some of the "Actions" that they are looking to perform. This section only allows you to run a query while custom columns allows for all of these things:
The event handlers is an upgraded version of this menu, so if all of this could be streamlined into a single section with event handlers it would be awesome! 