Would you like this "once per turn" feature to be present even for other Bonus Actions?
I would strongly prefer that they stuck to the system rules in general:
You can take a bonus action only when a special ability, spell, or other feature of the game states that you can do something as a bonus action. You otherwise don’t have a bonus action to take.
You can take only one bonus action on your turn, so you must choose which bonus action to use when you have more than one available.
That way they wouldn't have to worry about adding extra code weight to each and every bonus action and new bonus action they invent, about limiting it to once per turn - it would be automatically covered by there being only one bonus action per turn.
