That’s a perfectly valid solution, and you are right, it’s easier. Buttons make things happen on the UI, and the system is designed so that it only sends stuff to the server when there is something to send. So a button in and of itself is a bit difficult to simply trigger stuff server side. Adding a checkbox is something that will trigger the server to do something, so it’s a good way to trigger your update.
As far as the specifics you are asking about, you don’t need to bind the button to anything. A button doesn’t display anything, so the only reason to bind it to anything is for something like row rules. Once you make the button, you can use the wizard to create a button event for you. This gives you an empty method to put whatever code you want into that that method that will fire when you click it. So what I would probably do is change your new checkbox, then add an oTrans.Update() and it should trigger your update method. See the post below about using oTrans.Update()
Or… Like you said, put the check box on there, check the box and hit save.