Fanaelialae
Legend
If you're worried about making a blanket ruling, simply say that the Bag of Tricks can be activated using an action OR a bonus action. Then, if there is anything that you do want to limit, you can leave them as bonus action only.
That said, I don't disagree with your ruling. By RAW, you cannot swap an action for another bonus action. (If you do go the route of allowing them to be traded, keep in mind that with action surge that could mean 3 bonus actions per turn. That isn't necessarily broken, but should be factored into your calculus.)
That said, I don't disagree with your ruling. By RAW, you cannot swap an action for another bonus action. (If you do go the route of allowing them to be traded, keep in mind that with action surge that could mean 3 bonus actions per turn. That isn't necessarily broken, but should be factored into your calculus.)