Is this cancel button needed?

In this UI it is possible to type in text in an input box, press Enter and the text would get converted into a tag visually (and in JSON). After the tag is typed, the cursor would be ready for the user to type up a new tag, etc.

Think simple tags input UI's, like on any StackExchange Ask a Question UI.

The problem arose when someone mentioned they were not sure if they needed to press Enter or Space bar or anything else on the keyboard. So naturally we decided to add on-screen floating with cursor buttons - OK (same as Enter) and 'X' (removes the whole typed text up until the first previous tag). So the buttons move to the left with the cursor. Have a look at the screenshot.

Someone in the team raised a question of whether the 'X' button is even needed. They said:

Couldn't the user just backspace it?

What are your thoughts? Is there a need for this 'X' button? Would it make it easier? Or would it only make user use their mouse more instead of just backspacing?