- Can execute web services. One can create a Salesforce web service in Apex that can then be invoked from a record. This is useful for doing various processing on a record. For example, the candidate has been approved and now you want to update the status and email the individual in one button click.
- UX Experience calling web services. If the web service does a moderate level of processing, the user may have to wait seconds for the operation to complete. Salesforce doesn’t automatically update the UI to indicate that something is happening. It’s up to the developer to update the UI to reflect the processing is in-progress and to notify the user with a message of the operation’s success or failure.
- Have to add dependent libraries like JQuery through RequireScript syntax or other means. Open jQuery Dialog from Custom Button for more info.