Is a split button valid without proper visual grouping

Yes, it could be considered valid, When the actions inside dropdown are on a similar level to "Reply".

1. When would a user be likely to use the split button in Word?
2. What is the use of split button on the monitor?
3. How do you create a split button in HTML?

When would a user be likely to use the split button in Word?

Split buttons are most useful in repeat-use desktop applications with a large number of commands that need to be consolidated.

What is the use of split button on the monitor?

The Split Button is a composite control with which the user can select a default value bound to a primary button, or select from a list of mutually exclusive values displayed in a drop-down list bound to a secondary button.

How do you create a split button in HTML?

Example Explained. Use any element to open the dropdown menu, e.g. a <button>, <a> or <p> element. Use a container element (like <div>) to create the dropdown menu and add the dropdown links inside it. Wrap a <div> element around the button and the <div> to position the dropdown menu correctly with CSS.